TW202212313A - Vinyl acetate, vinyl acetate polymer, and vinyl alcohol polymer - Google Patents

Abstract

Provided are: a trackable vinyl acetate; a polymer containing the vinyl acetate; and a vinyl alcohol polymer that is a saponified product of said polymer. A vinyl acetate wherein the proportion of carbon-14 to all carbon atoms is at least 1.0×10<SP>-14</SP>. A vinyl acetate polymer comprising the vinyl acetate as a monomeric unit. A vinyl alcohol polymer obtained by saponification of the vinyl acetate polymer.

Description

Vinyl acetate, vinyl acetate polymers and vinyl alcohol polymers

The present invention relates to traceable vinyl acetate, polymers containing the vinyl acetate as monomer units, and saponified products thereof.

Vinyl acetate is used as a raw material for vinyl acetate resin or vinyl alcohol resin, and is further used as a monomer for copolymerization with ethylene, styrene, acrylate, methacrylate, and the like. In addition, the obtained resins and copolymers are important industrial materials widely used in a wide range of fields such as paints, adhesives, and fiber processing agents.

Among them, vinyl alcohol polymer (hereinafter sometimes referred to as PVOH) obtained by polymerizing vinyl acetate and then saponifying the obtained polymer is a rare crystalline water-soluble polymer, which utilizes its excellent water solubility and film properties. (strength, oil resistance, film-forming properties, oxygen barrier properties, etc.) and are widely used in emulsifiers, suspending agents, surfactants, various binders, adhesives, fiber processing agents, paper processing agents, films, fibers, fabrics Wait.

In addition, the ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as EVOH) obtained by copolymerizing vinyl acetate and ethylene and then saponifying the obtained copolymer has transparency, barrier properties to various gases such as oxygen, and fragrance retention properties. , solvent resistance, oil resistance, non-charged properties, mechanical strength, etc. are excellent, taking advantage of this feature, it is widely used in various packaging containers such as food packaging containers, pharmaceutical packaging containers, industrial pharmaceutical packaging containers, and pesticide packaging containers. When producing such a molded product, secondary processing is often performed after melt-molding the ethylene-vinyl alcohol copolymer. For example, processes such as stretching for the purpose of improving mechanical strength or thermoforming of a multilayer sheet including an ethylene-vinyl alcohol copolymer layer in order to form a container shape are widely performed.

In this way, vinyl alcohol polymers and ethylene-vinyl alcohol copolymers are widely used, and it is therefore an imperative for suppliers to provide high-quality products to the market. Also, for brand marketing, a method of distinguishing the own company's products from other companies' products is required.

For example, ethylene-vinyl alcohol copolymers used in gas barrier layers of commercial packaging containers are formed into packaging containers by thermoforming, but ethylene-vinyl alcohol copolymers may form insoluble due to the thermal history experienced during thermoforming glue in solvent. Therefore, even if the packaging container is recovered, the ethylene-vinyl alcohol copolymer used is extracted with a solvent, and its molecular weight is to be measured, it is difficult to accurately measure the molecular weight in many cases. Therefore, it is not possible to determine whether or not it is the ethylene-vinyl alcohol copolymer of the company only by analyzing the molded body.

Therefore, the produced vinyl acetate, polymers or copolymers obtained therefrom, and saponified products thereof are used in paints, adhesives, fiber processing agents, paper processing agents, films, fibers, and fabrics through many passages. , food packaging containers, pharmaceutical packaging containers, industrial pharmaceutical packaging containers, pesticide packaging containers, etc. are then discarded. In this case, it is difficult to determine which factory and production line the resin and the packaging container after use are manufactured by. In addition, it is also difficult to track the quality survey of the company's products during use or after use, the environmental impact after disposal, and the decomposability in the soil.

As one of the tracking methods for in-house products, for example, a method of adding a tracking substance to vinyl alcohol polymers has been conceived. However, the addition of a tracer has the added cost of increasing the performance of the vinyl alcohol polymer.

[The problem to be solved by the invention]

The present inventors focused on the carbon isotopes contained in vinyl acetate and found that by using vinyl acetate containing a predetermined amount of a specific carbon isotope, the resulting polymers and copolymers can be traced, even if the final product is discarded. It can be judged whether its raw materials are products of its own company.

That is, the object of the present invention is to provide a traceable vinyl acetate, a polymer containing the vinyl acetate as a monomer unit, and a vinyl alcohol polymer of its saponification. [means to solve the problem]

The present invention provides vinyl acetate shown below, a polymer containing the vinyl acetate as a monomer unit, and a saponified product thereof.

[1] Vinyl acetate wherein the ratio of carbon 14 to all carbons is 1.0×10 ⁻¹⁴ or more.

[2] The vinyl acetate of the aforementioned [1], wherein the carbon stable isotope ratio is -20‰ or more.

[3] The vinyl acetate of the aforementioned [1], wherein the carbon stable isotope ratio is less than -20‰.

[4] The vinyl acetate according to any one of the aforementioned [1] to [3], which contains more than 0 ppm and 100 ppm or less of a sulfur component. [5] The vinyl acetate of the aforementioned [4], wherein the sulfur component is dimethyl sulfide or dimethyl sulfoxide.

[6] The vinyl acetate according to any one of the aforementioned [1] to [5], which contains 10 ppm to 1,500 ppm of the acetate.

[7] The vinyl acetate according to the aforementioned [6], wherein the aforementioned acetate is at least one of methyl acetate and ethyl acetate.

[8] The vinyl acetate according to any one of the aforementioned [1] to [7], which contains more than 0 ppm and 100 ppm or less of a polymerization inhibitor.

[9] The vinyl acetate according to any one of the aforementioned [1] to [8], comprising 1 ppm to 500 ppm of at least one compound selected from the group consisting of polyvalent carboxylic acids, hydroxycarboxylic acids, and hydroxylactone-based compounds.

[10] The vinyl acetate according to any one of the aforementioned [1] to [9], which contains 0.001 to 10 parts by mass of acetaldehyde dimethyl acetal.

[11] A vinyl acetate polymer containing the vinyl acetate as any one of the aforementioned [1] to [10] as a monomer unit.

[12] A vinyl alcohol polymer obtained by saponifying the vinyl acetate polymer of the aforementioned [11].

[13] The vinyl alcohol polymer according to the aforementioned [12], further contains ethylene units, and its content is 1 mol % or more and 60 mol % or less.

[14] The vinyl alcohol polymer according to the aforementioned [12] or [13], wherein the degree of saponification is 80 mol% or more.

[15] The vinyl alcohol polymer according to any one of the aforementioned [12] to [14], wherein the viscosity average degree of polymerization is 200 or more and 5,000 or less.

[16] The vinyl alcohol polymer according to any one of the aforementioned [12] to [15], wherein the content of the 1,2-diol bond is 0.2 mol % or more and 2 mol % or less.

[17] The vinyl alcohol polymer according to any one of the aforementioned [12] to [16], wherein the ratio of carbon 14 to all carbons is 1.0×10 ⁻¹⁴ or more.

[18] The vinyl alcohol polymer according to any one of the aforementioned [12] to [17], wherein the carbon stable isotope ratio is -20‰ or more.

[19] The vinyl alcohol polymer according to any one of the aforementioned [12] to [17], wherein the carbon stable isotope ratio is less than -20‰.

[20] The vinyl alcohol polymer according to any one of the aforementioned [12] to [19], wherein the sulfur content exceeds 0 ppm and is 100 ppm or less. [twenty one] The vinyl alcohol polymer according to the aforementioned [20], wherein the sulfur component is dimethyl sulfide or dimethyl sulfoxide.

[twenty two] The vinyl alcohol polymer according to any one of the aforementioned [12] to [21], wherein the ethylene unit content is 1 mol % or more and 15 mol % or less, and the degree of saponification is 85 mol % or more and 99.9 mol % or less, The polymer terminal has a propyl group, and the content of the propyl group is 0.0005 mol % or more and 0.1 mol % or less with respect to all the monomer units.

[twenty three] The vinyl alcohol polymer according to any one of the aforementioned [12] to [22], wherein the polymer terminal has an alkoxy group, and the content of the aforementioned alkoxy group is 0.0005 mol % or more and 1 mol % with respect to all monomer units the following.

[twenty four] The vinyl alcohol polymer according to any one of the aforementioned [12] to [23], wherein the polymer terminal has the following structures (I) and (II), and the total content of the structures (I) and (II) is relative to All monomer units constituting the vinyl alcohol polymer are 0.001 mol % or more and 0.1 mol % or less.

(式中，Y為氫原子或甲基)

(in the formula, Y is a hydrogen atom or a methyl group)

(式中，Z為氫原子或甲基)

(in the formula, Z is a hydrogen atom or a methyl group)

[25] The vinyl alcohol polymer of the aforementioned [24], wherein the ethylene unit content is 1 mol % or more and 15 mol % or less, and the degree of saponification is 85 mol % or more and 99.9 mol % or less, The molar ratio R[I/(I+II)] of the structure (I) to the total amount of the aforementioned structure (I) and the aforementioned structure (II) satisfies the following formula (1): R＜0.92-Et/100 (1) (In the formula (1), Et is the aforementioned ethylene unit content (mol %)).

[26] The vinyl alcohol polymer according to any one of the aforementioned [13], [22] or [25], wherein the block character of the ethylene unit is 0.90 to 0.99.

[27] The vinyl alcohol polymer according to any one of the aforementioned [24] or [25], wherein the ethylene unit content is 15 mol % or more and 60 mol % or less, and the degree of saponification is 85 mol % or more and 99.9 mol % or less, The total content of the aforementioned structure (I) and the aforementioned structure (II) is 0.002 mol % or more and 0.02 mol % or less with respect to all the monomer units constituting the vinyl alcohol polymer, and the structure (I) is relative to the aforementioned structure (I). ) and the total molar ratio R[I/(I+II)] of the aforementioned structure (II) satisfies the following formula (2) represented by the ethylene unit content Et in the vinyl alcohol polymer: 0.8<R+Et/100 (2).

[28] A method for tracing a polymer using vinyl acetate in which the ratio of carbon 14 to all carbons is 1.0×10 ⁻¹⁴ or more.

[29] The tracking method for vinyl acetate described in the aforementioned [28], wherein the carbon stable isotope ratio of vinyl acetate is -20‰ or more.

[30] The tracking method for vinyl acetate as described in the aforementioned [28], wherein the carbon stable isotope ratio of vinyl acetate is less than -20‰.

[31] A tracking method for a polymer using a vinyl acetate polymer containing the vinyl acetate as described in any one of the aforementioned [28] to [30] as a monomer unit.

[32] A method for tracing a polymer using a vinyl alcohol polymer obtained by saponifying the vinyl acetate polymer of the aforementioned [31]. [Effect of invention]

According to the present invention, a traceable vinyl acetate, a polymer containing the vinyl acetate, and a vinyl alcohol polymer of a saponified product thereof can be provided.

[Form for carrying out the invention]

The vinyl acetate of the present invention, the vinyl acetate polymer obtained by polymerizing it, and the vinyl alcohol polymer of its saponification will be explained in detail below.

In vinyl acetate obtained from conventional petroleum raw materials, the ratio of carbon 14 (hereinafter sometimes referred to as ¹⁴ C) to all carbons (hereinafter sometimes referred to as ¹⁴ C/C) is less than 1.0×10 ^-14 , relative to Therefore, in the vinyl acetate of the present invention, ¹⁴ C/C is 1.0×10 ⁻¹⁴ or more. All carbon refers to carbon containing all isotopes of carbon.

From the viewpoint of easy tracking, ¹⁴ C/C is preferably 1.0×10 ^-13 or more, more preferably 5.0×10 ^-13 or more. When almost 100% by mass is non-petrochemical raw materials, the upper limit of ¹⁴ C/C is 1.2×10 ^-12 , but the ¹⁴ C/C of a reference natural product such as an oxalic acid standard can also be measured arbitrarily, and this value can be calculated. Set as the upper limit value.

As a method of controlling the above-mentioned range of ¹⁴ C/C, a method of using vinyl acetate derived from natural products as described later has been thought of. There is artificially derived carbon 14 in nature, and the concentration of carbon 14 in natural products fluctuates from time to time. Therefore, when using vinyl acetate derived from natural products, the concentration of carbon 14 in natural products can be appropriately corrected to obtain the concentration of carbon 14 in vinyl acetate. ¹⁴ C/C. In addition, the half-life of carbon 14 is 5,730 years, and the reduction in the amount of carbon 14 can be ignored if the period from the manufacture of general chemical products to the time when they appear on the market is considered.

The quantitative determination of carbon 13 (hereinafter sometimes referred to as ¹³ C) and carbon 14 is as long as the carbon dioxide is analyzed by accelerator mass spectrometry (AMS method; The graphite of the reducing material is sufficient. For example, with respect to graphite ionized by irradiation with a Cs beam, the amounts of carbon 12 ions, carbon 13 ions, and carbon 14 ions are respectively measured.

¹⁴ C/C, as mentioned above, is obtained by comparing and measuring the carbon 14 content in oxalic acid, a standard material produced by the National Institute of Standards and Technology, after it becomes carbon dioxide or graphite by accelerator mass analysis. out.

The aforementioned vinyl acetate can be synthesized, for example, in the following manner. Usually, vinyl acetate can be obtained by gas-phase reaction of ethylene, acetic acid and oxygen in the presence of a catalyst. At this time, either or both of the ethylene and the acetic acid are used which contain a predetermined amount of carbon 14, whereby vinyl acetate containing a predetermined amount of carbon 14 is obtained. Examples of ethylene and acetic acid containing a predetermined amount of carbon 14 include biomass-derived ethylene and acetic acid.

The aforementioned biomass refers to an industrial resource derived from existing biological constituent substances, which is a non-thirsty resource, which is a renewable biological-derived organic resource and excludes petrochemical resources.

Biomass absorbs carbon dioxide from the atmosphere through photosynthesis during its growth. Therefore, even if carbon dioxide is emitted by burning biomass, the overall amount of carbon dioxide in the atmosphere does not increase. This property is called carbon neutrality, and it is preferable to use biomass-derived ethylene and/or acetic acid from the viewpoint of the global environment.

The biomass may be derived from a single source or may be a mixture, and examples thereof include cellulose-based crops such as pulp, kenaf, wheat straw, straw, waste paper, and paper residues, rapeseed oil, cottonseed oil, and soybean oil. , coconut oil, castor oil and other oils, corn, potato, wheat, rice, rice husk, rice bran, old rice, cassava, sago and other carbohydrate crops, pine root oil, orange oil, eucalyptus oil and other essential oils, and wood, Charcoal, compost, natural rubber, cotton, sugar cane, bagasse, bagasse, buckwheat, soybean, pulp black liquor, vegetable oil residue, etc. In addition, biomass is not limited to biofuel crops, and examples thereof include agricultural residues, municipal wastes, industrial wastes, paper industry sediments, pasture wastes, wood and forest wastes, and the like.

The carbon derived from the above-mentioned biomass means the carbon existing as carbon dioxide in the atmosphere, which is taken into a plant, and the carbon exists in vinyl acetate synthesized from this as a raw material. The atmosphere contains a predetermined amount of carbon 14, so the ethylene or acetic acid derived from the biomass ingested carbon dioxide in the atmosphere also contains a predetermined amount of carbon 14. Generally, in biomass-derived ethylene or acetic acid, carbon 14 is contained in a ratio of 1.0×10 ⁻¹² or more with respect to all carbon systems.

On the other hand, petrochemical resources such as petroleum contain almost no carbon 14, and in ethylene or acetic acid derived from petrochemical resources, the ratio of carbon 14 to all carbon is less than 1.0×10 ⁻¹⁴ . Therefore, by using biomass-derived ethylene and acetic acid together with petrochemical-derived ethylene and acetic acid as raw materials of vinyl acetate, the ¹⁴ C/C of the obtained vinyl acetate can be adjusted to a desired value. For example, vinyl acetate obtained from biomass-derived ethylene and biomass-derived acetic acid, and acetic acid obtained from petrochemical resource-derived ethylene and petrochemical resource-derived acetic acid can also be used to make ¹⁴ C/C an expected value. Vinyl acetate can also be mixed with ethylene and/or acetic acid derived from biomass and ethylene and/or acetic acid derived from petrochemical resources in a desired ratio to obtain vinyl acetate.

In addition, the molecular weight of ethylene derived from carbon 12 (hereinafter sometimes referred to as ¹² C) is 28.05, and the molecular weight of acetic acid is 60.05. On the other hand, ethylene and acetic acid containing a large amount of carbon 13 and carbon 14 have large molecular weights. Therefore, in general, the boiling point of ethylene is -103.7°C, and the boiling point of acetic acid is 117.9°C, and the boiling point thereof is slightly higher. The amount of carbon 13 and carbon 14 can be adjusted by utilizing the difference in boiling point caused by the molecular weight ratio, that is, the smaller the molecular weight, the lower the boiling point. Specifically, ethanol, which is a raw material of ethylene and acetic acid, ethylene obtained by dehydration reaction of ethanol, and acetic acid obtained by oxidation reaction of ethanol are purified by distillation, and gas-phase dehydration and gas-phase oxidation of ethanol are used. Gasification can bring carbon 13 or carbon 14 to the desired content.

By making the ratio of carbon 14 contained in vinyl acetate into the aforementioned range, it can be distinguished from general vinyl acetate obtained from petroleum-derived ethylene. In addition, ¹⁴ C/C can be appropriately changed for each product, each batch number, etc., which can also be used to determine which product it is used for from the recycled waste. The aforementioned vinyl acetate of the present invention can thus be traced after manufacture.

In addition to making the ratio of carbon 14 in vinyl acetate within the aforementioned range, it is preferable to make the carbon stable isotope ratio (hereinafter sometimes referred to as δ ¹³ C) within a specific range from the viewpoint of improving tracking accuracy.

The carbon stable isotope ratio refers to the ratio of carbon 13 to carbon 12 among the three isotopes of carbon atoms existing in nature, carbon 12, carbon 13 and carbon 14. The carbon stable isotope ratio is represented by a deviation from a standard substance, and is a value (delta value) defined by the following formula (3).

δ ¹³ C[‰]={( ¹³ C/ ¹² C) _sample /( ¹³ C/ ¹² C) _PDB -1.0}×1,000 (3)

Here, [( ¹³ C/ ¹² C) _sample ] represents the stable isotope ratio of the measurement object, and [( ¹³ C/ ¹² C) _PDB ] represents the stable isotope ratio of the standard substance. The subscript PDB is the abbreviation of "Pee Dee Belemnite", which represents a fossil of Belemnites (Belemnites) containing calcium carbonate (the Belemnites fossils unearthed from the PeeDee layer in South Carolina are used as the standard material), which is used as ¹³ Standard for C/ ^12C ratio. In addition, "carbon stable isotope ratio (δ ¹³ C)" is measured by accelerator mass spectrometry. In addition, since the reference material is rare, a working standard whose stable isotope ratio to the reference material is known can also be used.

By using the vinyl acetate whose δ ¹³ C is above -20‰ or the vinyl acetate whose δ 13 C is less than -20‰, the tracking accuracy can be further improved. It is convenient to use the above-mentioned biomass-derived ethylene or acetic acid as a method for making δ ¹³ C within the aforementioned range.

In the case of using biomass-derived ethylene and acetic acid, as described later, biomass is roughly divided into C3-derived plants such as sweet potatoes, sugar beets, rice, trees, and algae, and C4-derived plants such as corn, sugarcane, and cassava, The δ ¹³ C of the two is different.

Plants are classified into the following three types according to the types of initial carbon dioxide fixation products in the carbonic acid fixation pathway of photosynthesis: C3 plants, C4 plants, and succulent photosynthetic (CAM/Crassulacean Acid Metabolism) plants (below Also described as CAM plants).

More than 90% of plants on earth belong to C3 plants, including agriculturally useful plants such as rice, barley, tobacco, wheat, potato, oil palm, and the like. In the photosynthesis pathway of C3 plants, the enzyme related to carbon dioxide fixation is ribulose-1,5-bisphosphate carboxylase, which has a low affinity for carbon dioxide and a high affinity for oxygen, so the carbon dioxide fixation reaction , or even the inefficiency of the photosynthesis reaction. Such plants with only the Calvin-Benson cycle are called C3 plants.

When δ ¹³ C is less than -20‰, although these C3 plants and their mixtures are widely used as carbon sources, rice, wheat, potato and palm oil are preferably used as carbon sources in terms of production volume and cost.

In the case of using biomass derived from C3 plants, the carbon stable isotope ratio (δ ¹³ C) of vinyl acetate using the obtained ethylene and/or acetic acid as a raw material improves the tracking accuracy of polymers using the vinyl acetate, etc. From the viewpoint of , it is preferably less than -60 to -20‰, more preferably -50 to -22‰, further preferably -45 to -25‰, and particularly preferably -40 to -26‰.

C4 plants refer to plants that perform C4-type photosynthesis. In the process of photosynthesis, in addition to the Calvin-Bonson cycle, which belongs to the general carbon dioxide reduction cycle, there is one type of photosynthesis that has the C4 pathway to concentrate carbon dioxide. state. The enzyme involved in carbon dioxide fixation in the photosynthetic pathway of this C4 plant is phosphoenolpyruvate carboxykinase. The characteristics of this enzyme are that it is not hindered by the activity of oxygen, has a high immobilization energy of carbon dioxide, and has well-developed chloroplasts in the vascular bundle sheath cells. Among the representative C4 plants, there are corn, sugarcane, cassava, sorghum, miscanthus, geranium, rhododendron, Brachiaria tetragoni, millet, barnyardgrass, hazelnut, broom tree, etc. The other names of the tree are broom grass, Bassia scoparia, and Kochia green. This C4 plant can fix carbon dioxide efficiently. Also, C3 plants are not easy to collect carbon dioxide at high temperatures, but C4 plants do not have such a phenomenon. Moreover, sufficient photosynthesis can be carried out with a small amount of water. Its physiological adaptability can cope with harsh climates for plants such as high temperature, dryness, low carbon dioxide, and nitrogen-poor soils.

When δ ¹³ C is -20‰ or more, these C4 plants and their mixtures are widely used as carbon sources, but corn, sugarcane, and cassava are preferably used as carbon sources in terms of production volume and cost.

CAM plants have a photosynthetic system adapted to dry environments, which is considered to be an evolutionary form of C3 photosynthesis. As a CAM plant, Cactaceae (Cactaceae), Crassulaceae (Crassulaceae), Euphorbiaceae (Euphorbiaceae) etc. are mentioned, for example. The carbon stable isotope ratio of CAM plants is generally in the range of -35‰ to -10‰, and these CAM plants can also be used as raw materials according to demand.

As described above, the δ ¹³ C of vinyl acetate mainly depends on the δ ¹³ C of the raw material, and the δ ¹³ C of the obtained vinyl acetate can be adjusted by appropriately mixing ethylene and/or acetic acid with different carbon isotope ratios. For example, if vinyl acetate is produced by using ethylene and/or acetic acid using biomass of C4 plants and C3 plants as raw materials, and the two are mixed in a predetermined ratio, the value of ¹⁴ C and δ can be appropriately adjusted at the same time. ¹³ C value.

Vinyl acetate polymers and their saponified products, with trace amounts of cross-linking agents, additives and grafting components used in response to needs, but usually constitute 65 mass of the main components of the carbon source of these vinyl acetate polymers and their saponified products % or more are derived from vinyl acetate, so by controlling the δ ¹³ C and ¹⁴ C/C of vinyl acetate, the δ ¹³ C and ¹⁴ C of the vinyl acetate polymer and its saponified products obtained from the vinyl acetate can be controlled C/C.

In addition, the vinyl acetate of the present invention can make ¹⁴ C/C and δ ¹³ C in the aforementioned range according to needs, and vinyl acetates having different ¹⁴ C/C or δ ¹³ C can be mixed and used.

For example, not only can vinyl acetate exhibiting a predetermined δ ¹³ C be obtained using raw materials derived from C3 plants, but also vinyl acetates with different δ ¹³ C can be mixed to contain a predetermined δ ¹³ C, that is, the monomers of C3 plants cannot achieve this. The δ ¹³ C becomes more specific δ ¹³ C, whereby the tracking accuracy of the obtained vinyl acetate polymer and its saponification can be further improved. Specifically, if a different δ ¹³ C raw material is used, the statistical analysis value obtained by analyzing the carbon stable isotope ratio becomes a fixed value, so it can be distinguished from other raw materials. Therefore, the vinyl acetate polymer produced from this raw material is The δ ¹³ C of its saponified product also has an inherent analytical value, so it is easy to identify and trace.

When mixing and using a plurality of vinyl acetates having different δ ¹³ C, the mixing may be performed at the stage of refining vinyl acetate as the final product, or the crude vinyl acetate may be mixed in a previous stage and then purified by distillation. Moreover, after mixing different ethylene and/or acetic acid, you may make it react as vinyl acetate.

Among them, from the viewpoints of adjustment of trace components and variety of raw materials, and from the viewpoint of further improving the traceability of the vinyl acetate polymer and its saponified products obtained, those using petrochemical raw materials and non-petrochemical raw materials are preferred. A variety of feedstock sources are available for the aforementioned vinyl acetate process. The mixing ratio in the aforementioned manufacturing method can be fixed, and the ratio can also be changed with respect to time or with respect to the vinyl acetate polymer and its saponified product.

In addition, since vinyl acetate is not 100% derived from petrochemical raw materials, nor is 100% vinyl acetate derived from non-petrochemical raw materials, the resulting vinyl acetate polymer and its saponified products have a unique and specific ¹⁴ C/C , and the tracking accuracy can be further improved, so it is preferable. The ratio of the non-petrochemical raw material to the petrochemical raw material can be confirmed by quantifying ¹⁴ C/C with respect to the obtained vinyl acetate polymer and its saponified product.

Furthermore, by using a plurality of raw material sources of petrochemical raw materials and non-petrochemical raw materials in combination as vinyl acetate, fluctuations in the raw material cost of the obtained resin can be suppressed. Vinyl acetate polymers and their saponified products obtained from the aforementioned vinyl acetate are widely used because of their excellent cost and stability of raw material sources. For example, if biomass ethylene obtained from biomass ethanol or biomass naphtha is used as a non-petrochemical raw material for vinyl acetate, and ethylene derived from naphtha is used as a petrochemical raw material, the aforementioned effects can be further expected.

The vinyl acetate having the above-mentioned specific carbon isotope ratio preferably further contains the following compounds.

In the vinyl acetate of this invention, it is preferable to contain the sulfur component in excess of 0 ppm and 100 ppm or less. As described above, the vinyl acetate of the present invention can easily control ¹⁴ C/C and δ ¹³ C by using biomass-derived ethylene and/or acetic acid as raw materials. When biomass-derived ethylene and/or vinyl acetate are used, biomass-derived vinyl acetate containing an organic sulfur compound can be obtained. On the other hand, since the petroleum-derived vinyl acetate is desulfurized during the cracking of the naphtha, the sulfur content is smaller than that of the biomass-derived vinyl acetate. Therefore, by comparing the content of sulfur components, it is easier to trace the vinyl acetate and vinyl acetate polymers derived from biomass. In particular, biomass-derived vinyl acetate and vinyl acetate polymers contain dimethyl sulfide or dimethyl sulfite as a sulfur component, so vinyl acetate having dimethyl sulfide or dimethyl sulfite becomes easier to track.

The vinyl alcohol polymer obtained by copolymerizing vinyl acetate and ethylene in the coexistence of acetate and saponifying it has improved melt extrusion stability and is also excellent in hue. From this point of view, the aforementioned vinyl acetate The ester preferably contains acetate.

When the acetate is polymerized, the aliphatic alcohol having 4 or less carbon atoms used as the polymerization solvent undergoes a transesterification reaction with vinyl acetate, according to the following formula (4):

(in the formula, R is an alkyl group having 4 or less carbon atoms) to generate acetaldehyde. When the content of acetaldehyde exceeds 200 ppm, the melt extrusion stability and melt moldability of the vinyl alcohol polymer may be deteriorated, and coloring and gum formation may occur when used as a molded product.

Regarding the adverse effects caused by acetaldehyde, the mechanism of its occurrence has not been clarified, but acetaldehyde acts as a chain transfer agent during polymerization and affects the degree of polymerization, degree of polymerization distribution, branching, etc. of the obtained ethylene-vinyl acetate copolymer. As a result, it is considered that it adversely affects the melt extrusion stability and melt moldability of the ethylene-vinyl alcohol copolymer. In addition, acetaldehyde is condensed in the polymerization of ethylene and vinyl acetate, and is converted into a condensate that is easy to color and produce glue, and the condensate cannot be removed in the subsequent purification steps of the polymer. Therefore, it is considered that ethylene- Vinyl alcohol copolymers are markedly colored and glued when used as moldings.

Since the above-mentioned transesterification reaction is an equilibrium reaction, the addition of acetate has the effect of suppressing the generation of acetaldehyde.

As the acetate, from the viewpoints of melt extrusion stability and hue, saturated acetate is preferred. Saturated acetate refers to an ester comprising acetic acid and a saturated aliphatic alcohol. The saturated acetate is preferably an ester of acetic acid and an aliphatic alcohol having 4 or less carbon atoms, more preferably methyl acetate or ethyl acetate.

The content ratio of acetate to vinyl acetate is preferably 10 ppm to 1,500 ppm, more preferably 30 ppm to 1,300 ppm, still more preferably 50 ppm to 1,200 ppm, particularly preferably 100 ppm to 1,000 ppm.

Acetate can also be used by mixing a plurality of acetates. In this case, the total amount of the content of each acetate is preferably within the aforementioned range.

From the viewpoint of storage stability, the vinyl acetate of the present invention preferably contains a polymerization inhibitor. Examples of the polymerization inhibitor include p-benzoquinone, tert-butylhydroquinone, 4-tert-butylcatechol, cuprophene, 2,6-di-tert-butyl-4-cresol, N , N-diethylhydroxylamine, hydroquinone, p-methoxyphenol, N-nitroso-N-phenylhydroxylamine aluminum, phenothia, tert-butylhydroquinone, dibutylhydroxytoluene, 1 , 1-diphenyl-2-trinitrophenylhydrazine, p-methoxyphenol (mequinol).

The content of the polymerization inhibitor is preferably more than 0 ppm and 100 ppm or less, more preferably more than 0 ppm and 50 ppm or less, still more preferably more than 0 ppm and 30 ppm or less, and particularly preferably 1 ppm to 30 ppm. A large amount of the polymerization inhibitor may delay the polymerization rate and may cause coloration after production, and if it is too small, not only the storage stability of vinyl acetate but also the polymerization may be slowed down.

The vinyl acetate of the present invention is preferably from the viewpoints of the hue of the ethylene-vinyl alcohol copolymer obtained by copolymerizing vinyl acetate and ethylene and saponifying the ethylene-vinyl alcohol copolymer and suppressing the generation of odor and fish eyes during film formation. At least one of polyvalent carboxylic acid, hydroxycarboxylic acid, and hydroxylactone-based compound is contained.

Examples of polyvalent carboxylic acids and hydroxycarboxylic acids include malonic acid, succinic acid, maleic acid, phthalic acid, oxalic acid, glutaric acid, glycolic acid, lactic acid, glycerin, apple, tartaric acid, citric acid, and salicylic acid. acid, etc., among them, citric acid is preferable.

The hydroxylactone-based compound is not particularly limited as long as it is a compound having a lactone ring and a hydroxyl group in the molecule, and examples thereof include L-ascorbic acid, erythorbic acid, glucono-δ-lactone, etc. Among them, L- Ascorbic acid, erythorbic acid.

The content of the polyvalent carboxylic acid, hydroxycarboxylic acid, and hydroxylactone-based compound is preferably 1 ppm to 1,000 ppm, more preferably 5 ppm to 500 ppm, and still more preferably 10 ppm to 300 ppm relative to vinyl acetate. When the content of the polyvalent carboxylic acid, hydroxycarboxylic acid, and hydroxylactone-based compound is less than 1 ppm, the aforementioned effect is small, and when it exceeds 1,000 ppm, the polymerization of vinyl acetate tends to be inhibited.

Examples of polycarboxylic acids, hydroxycarboxylic acids, and hydroxylactone-based compounds include a method of preliminarily adding to vinyl acetate, a method of adding vinyl acetate and a solvent to a polymerization system at the same time, a method of directly adding to a polymerization system, A method of pre-dissolving in a polymerization solvent and then adding to a polymerization system, a method of pre-mixing with other additives and then adding, a method of adding separately, and the like.

The vinyl acetate of the present invention preferably contains acetaldehyde dimethyl acetal from the viewpoints of controlling unevenness in the average degree of polymerization of the vinyl acetate polymer and the hue and solubility of polyvinyl alcohol obtained by saponification.

When the content of vinyl acetate is 100 parts by mass, the content of acetaldehyde dimethyl acetal is preferably 0.001 parts by mass to 10 parts by mass, more preferably 0.01 parts by mass to 7 parts by mass, still more preferably 0.1 parts by mass part to 5 parts by mass, particularly preferably 1 part to 5 parts by mass. When the content of acetaldehyde dimethyl acetal is less than 0.001 part by mass, the aforementioned effect is small, and when it exceeds 10 parts by mass, the polymerization of vinyl acetate tends to be inhibited.

The acetaldehyde dimethyl acetal includes, for example, a method of preliminarily adding to vinyl acetate, a method of adding vinyl acetate and a polymerization solvent described later to a polymerization system at the same time, a method of directly adding it to a polymerization system, and pre-dissolving in polymerization The method of adding to the polymerization system after using the solvent, the method of adding it after mixing with other additives in advance, the method of adding separately, etc.

By polymerizing or copolymerizing the aforementioned vinyl acetate of the present invention, a vinyl acetate polymer or copolymer containing vinyl acetate as a monomer can be obtained (hereinafter, the polymer and the copolymer are collectively described as a polymer). At the time of copolymerization, the monomer to be copolymerized may be any other monomer copolymerizable with vinyl acetate.

Examples of other copolymerizable monomers include ethylene; olefins having 3 to 30 carbon atoms such as propylene, 1-butene, and isobutylene; acrylic acid or its salts; methyl acrylate, ethyl acrylate, n-propyl acrylate, Acrylates such as isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, etc.; methacrylic acid or its salts; methyl acrylate Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, methacrylic acid 2-ethylhexyl ester, dodecyl methacrylate, octadecyl methacrylate and other methacrylates; acrylamide, N-methacrylamide, N-ethylacrylamide, N,N- Dimethacrylamide, diacetone acrylamide, acrylamide propane sulfonic acid or its salt, acrylamide propyl dimethylamine or its salt, N-methylol acrylamide or its derivatives and other acrylamides Amine derivatives; Methacrylamide, N-Methyl Methacrylamide, N-Ethyl Methacrylamide, Methacrylamide propane sulfonic acid or its salts, Methacrylamide propyl dimethacrylate Methylamine or its salt, N-methylolmethacrylamide or its derivatives and other methacrylamido derivatives; N-vinylformamide, N-vinylacetamide, N-vinylpyrrole N-vinyl amides such as pyridone; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether , vinyl ethers such as dodecyl vinyl ether and stearyl vinyl ether; vinyl cyanide such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride; acetic acid Allyl compounds such as allyl esters and allyl chloride; maleic acid or its salts, esters or anhydrides; Iconic acid or its salts, esters or anhydrides; vinylsilyl compounds such as vinyltrimethoxysilane; isopropylene acetate esters, etc.

In the polymerization of the aforementioned vinyl acetate, it is preferable to use an aliphatic alcohol having 4 or less carbon atoms as a polymerization solvent. When an aliphatic alcohol having 5 or more carbon atoms, an aromatic alcohol, or the like is used, the effects of the present invention cannot be sufficiently obtained. Examples of the aliphatic alcohol having 4 or less carbon atoms include methanol, ethanol, propanol, and butanol, among which methanol, ethanol, and propanol are preferred, methanol and ethanol are more preferred, and methanol is further preferred.

In the vinyl acetate of the present invention, as described above, since the ratio of carbon 14 to all carbons is 1.0×10 ⁻¹⁴ or more, carbon 14 to all carbons in the vinyl acetate polymer obtained by polymerizing the vinyl acetate is The ratio is 1.0×10 ^-14 or more. When vinyl acetate having a carbon stable isotope ratio of -20‰ or more is used as vinyl acetate, the carbon stable isotope ratio in the obtained vinyl acetate polymer is -20‰ or more. In addition, when vinyl acetate having a stable isotope ratio of less than -20‰ is used as vinyl acetate, the carbon stable isotope ratio in the obtained vinyl acetate polymer is less than -20‰.

When vinyl acetate contains more than 0 ppm and 100 ppm or less of sulfur content, the obtained vinyl acetate polymer contains more than 0 ppm and 100 ppm or less of sulfur content. The contained sulfur component is, as described above, preferably dimethyl sulfide or dimethyl sulfoxide from the viewpoint of easy traceability.

A vinyl alcohol polymer can be obtained by saponifying a polymer having the aforementioned vinyl acetate as a monomer unit. As described above, when a vinyl acetate polymer in which the ratio of carbon 14 to all carbons is 1.0 × 10 ^-14 or more is used, the ratio of carbon 14 to all carbons in the vinyl alcohol polymer obtained is 1.0 × 10 ^{- 14} and above. When a vinyl acetate polymer having a carbon stable isotope ratio of -20‰ or more is used as the vinyl acetate polymer, the carbon stable isotope ratio in the obtained vinyl alcohol polymer is -20‰ or more. Furthermore, when a vinyl acetate polymer having a carbon stable isotope ratio of less than -20‰ is used as the vinyl acetate polymer, the carbon stable isotope ratio in the obtained vinyl alcohol polymer is less than -20‰.

When the vinyl acetate polymer contains more than 0 ppm and 100 ppm or less of sulfur content, the obtained vinyl alcohol polymer contains more than 0 ppm and 100 ppm or less of sulfur content. The contained sulfur component is, as described above, preferably dimethyl sulfide or dimethyl sulfoxide from the viewpoint of easy traceability.

When the polymer having vinyl acetate as a monomer unit is a copolymer of other monomers that can be copolymerized with vinyl acetate, it is preferably a vinyl acetate-ethylene copolymer in which the other copolymerizable monomer is ethylene A saponified vinyl alcohol polymer containing ethylene units. When the vinyl alcohol polymer contains ethylene units, the content of the ethylene units is preferably 1 mol % or more and 60 mol % or less, more preferably 1 mol % or more and 55 mol % or less.

The degree of saponification of the vinyl alcohol polymer is preferably 80 mol% or more, more preferably 85 mol% or more, and even more preferably 90 mol% or more. The degree of saponification refers to the ratio of the molar number of vinyl alcohol units to the total molar number of vinyl alcohol units (typically vinyl ester monomer units) that can be converted into vinyl alcohol units by saponification. Ear%).

The degree of saponification of the vinyl alcohol polymer can be measured according to the description of JIS K 6726:1994. Specifically, when the degree of saponification is 99.5 mol % or less, the limiting viscosity [η] ( liter/g), and the viscosity-average degree of polymerization (P) was determined by the following formula. P=([η]×10 4/8.29) ^(1/0.62)

The degree of polymerization of the vinyl alcohol polymer is preferably 200 or more, more preferably 300 or more, still more preferably 500 or more, from the viewpoint of ensuring sufficient mechanical strength of the obtained film. Moreover, from the viewpoint of the productivity and water solubility of the vinyl alcohol polymer, the degree of polymerization is preferably 5,000 or less, and more preferably 3,000 or less.

The vinyl alcohol polymer preferably has a 1,2-diol bond. The content of the 1,2-diol bond is preferably 0.2 mol % or more, more preferably 0.3 mol % or more, still more preferably 0.4 mol % or more, and particularly preferably 0.5 mol % or more. Also, the content of the 1,2-diol bond is preferably 2 mol % or less, more preferably 1.5 mol % or less, still more preferably 1.3 mol % or less, and particularly preferably 1.0 mol % or less.

The vinyl alcohol polymer of the present invention is preferably based on all monomer units in the vinyl alcohol polymer from the viewpoints of the hue of the obtained film and the viscosity stability of the aqueous solution during film formation, in addition to the viewpoint of easy tracking. It contains 1 mol% or more and 15 mol% or less of ethylene units, has a degree of saponification of 85 mol% or more and 99.9 mol% or less, and has a propylene unit at the end, and the content of the aforementioned propyl group is 0.0005 mol per all monomer units. % or more of 0.1 mol or less of vinyl alcohol polymer (hereinafter sometimes referred to as ethylene-modified vinyl alcohol polymer).

The viscosity-average degree of polymerization of the ethylene-modified vinyl alcohol polymer is preferably 200 or more and 3,000 or less, more preferably 400 or more and 2,800 or less, and even more preferably 450 or more and 2,500 or less. The viscosity-average degree of polymerization is the same as above, and is a value measured in accordance with JIS K 6726:1994.

The saponification degree of the ethylene-modified vinyl alcohol polymer is preferably 80 mol % or more and 99.9 mol % or less, more preferably 90 mol % or more and 99.9 mol % or less.

The ethylene-modified vinyl alcohol polymer preferably has a propyl group of 0.0005 mol% or more and 0.10 mol% or less at one end, more preferably 0.001 mol% or more and 0.08 mol% or less, more preferably 0.005 mol% or less. More than mol% and less than 0.05mol%.

The method of introducing the propyl group is preferably, for example, a method of reacting ethylene with vinyl acetate in the presence of an initiator having a propyl group and a chain transfer agent in the polymerization step. Thus, by using together the initiator which has a propyl group, and the chain transfer agent which has a propyl group, the ethylene-modified vinyl alcohol polymer which introduce|transduced the propyl group of a specific amount at one side terminal can be manufactured efficiently.

Examples of the initiator having a propyl group include n-propyl peroxydicarbonate, 1,1'-propan-1-carbonitrile, and the like. In order to obtain the content of the propyl group, the use amount of the initiator having a propyl group is preferably 0.000125 mass % or more and 0.25 mass % or less, more preferably 0.0003 mass % or more and 0.2 mass % or less, with respect to vinyl acetate. Preferably it is 0.0005 mass % or more and 0.15 mass % or less.

As a chain transfer agent which has a propyl group, propanethiol, propionaldehyde, etc. are mentioned, for example. In order to obtain the content of the propyl group, the concentration of the chain transfer agent having a propyl group in the system is preferably 0.0001 mass % or more and 0.005 mass % or less with respect to vinyl acetate, more preferably 0.0002 mass % or more and 0.004 mass % Below, it is more preferable that it is 0.0003 mass % or more and 0.003 mass % or less.

The polymerization temperature is not particularly limited, but is preferably 0°C to 180°C, more preferably 20°C to 160°C, still more preferably 30°C to 150°C. When the polymerization is carried out below the boiling point of the solvent used in the polymerization step, it can be selected from reduced pressure boiling polymerization in which the polymerization is carried out while boiling the solvent under reduced pressure, and normal pressure in which the polymerization is carried out under normal pressure without boiling the solvent. Any method of non-boiling polymerization. Furthermore, when the polymerization is carried out at or above the boiling point of the solvent used in the polymerization step, there can be selected pressure non-boiling polymerization in which the polymerization is carried out under pressure without boiling the solvent, and polymerization under pressure while boiling the solvent. any method of pressurized boiling polymerization.

The ethylene pressure in the polymerization reactor in the polymerization step is not particularly limited, but is preferably 0.01 MPa to 0.9 MPa, more preferably 0.05 MPa to 0.7 MPa, still more preferably 0.1 MPa to 0.65 MPa.

The polymerization rate of vinyl acetate at the outlet of the polymerization reactor is not particularly limited, but is preferably from 10% to 90%, more preferably from 15% to 85%.

The alkoxy group content of the vinyl alcohol polymer obtained by polymerizing the aforementioned vinyl acetate of the present invention is based on all structural units (all monomer units and alkoxy groups) constituting the vinyl alcohol polymer, from the viewpoint of being easily traceable. The molar number of the unit) is preferably 0.0005 mol % to 1 mol %, more preferably 0.0007 mol % or more, still more preferably 0.001 mol % or more. On the other hand, the aforementioned content is preferably 0.5 mol % or less, and more preferably 0.3 mol % or less.

As a production method of the vinyl alcohol polymer containing the said alkoxy group, the method of saponifying the vinyl ester polymer obtained by copolymerizing the said vinyl acetate of this invention and the unsaturated monomer which has an alkoxy group is mentioned. The alkoxy group-containing monomer is not particularly limited as long as it has an alkoxy group and is an unsaturated monomer that can be copolymerized with vinyl ester, and examples thereof include alkyl vinyl ether, alkyl allyl ether, N-alkoxyalkyl(meth)acrylamides, etc., preferably N-alkoxyalkyl(meth)acrylamides. The alkoxy group-containing monomer may be used alone or in combination of two or more, but the former is preferred.

In the case of obtaining a vinyl alcohol polymer by polymerizing the aforementioned vinyl acetate and ethylene of the present invention, the polymer terminal has a structure (I) represented by the following structural formula (I) and a structure represented by the following structural formula (II) (II):

(in the formula, Y is a hydrogen atom or a methyl group)

(in the formula, Z is a hydrogen atom or a methyl group) The vinyl alcohol polymer in which the total amount of the structure (I) and the structure (II) is 0.001 mol % or more and 0.1 mol % or less with respect to all the monomer units, in addition to the viewpoint of easy traceability, the vinyl alcohol polymer is in the initial stage of melting. It is excellent in viscosity stability and can stabilize the melt-forming step, and is also preferable from the viewpoint of coloring resistance under high temperature and alkaline conditions such as 80°C. The total content is more preferably 0.07 mol % or less, still more preferably 0.05 mol % or less, and particularly preferably 0.02 mol % or less. On the other hand, the aforementioned total content is more preferably 0.002 mol % or more.

In addition, in this specification, the monomer units in the vinyl alcohol polymer refer to vinyl alcohol units and vinyl ester units, and in the case of copolymers with ethylene, refer to ethylene units and other monomer units that are copolymerized according to needs, All monomer units then means the total amount of molars of each monomer unit. At this time, the unit including the terminal structure represented by the structure (I) or the structure (II) is also included in the calculation of the monomer unit.

Both the structure (I) and the structure (II) are structures derived from the polymerization initiator used in the polymerization step. Among them, structure (I) includes a cyclic ester structure formed by the reaction of a nitrile group derived from a polymerization initiator and a hydroxyl group in the same molecule, and structure (II) is a structure before such a reaction occurs.

The aforementioned structure (I) can be introduced into a polymerization terminal by using an alkoxy group-containing azonitrile compound as a polymerization initiator. Examples of the alkoxy-containing azonitrile compound include 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (4-ethoxy-2,4-dimethylvaleronitrile), etc. Among them, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) is preferable. These alkoxy-containing azonitrile compounds do not cause abnormal decomposition due to contact with metals, and also have a high decomposition rate at low temperature. Therefore, by using the aforementioned azonitrile compound, ethylene and vinyl ester can be copolymerized safely, efficiently and economically.

The vinyl alcohol polymer having the aforementioned structures (I) and (II) at the polymer terminal preferably has a content of ethylene units of 1 mol % or more and 15 mol % or less from the viewpoint of the hydrophilicity of the vinyl alcohol polymer. , more preferably 1 mol% or more and 10 mol% or less, still more preferably 1 mol% or more and 8 mol% or less, and particularly preferably 1 mol% or more and 5 mol% or less.

The aforementioned vinyl alcohol polymer having the aforementioned structures (I) and (II) at the polymer terminal preferably has a viscosity-average degree of polymerization of 200 or more and 3,000 from the viewpoint of the water-resistant adhesive viscosity of the adhesive obtained from the vinyl alcohol polymer. Below, more preferably 400 or more and 2,800 or less, and even more preferably 450 or more and 2,500 or less.

In addition, the degree of saponification of the vinyl alcohol polymer having the structures (I) and (II) at the polymer terminal is the solubility in water and the water-resistant adhesiveness of the adhesive obtained from the vinyl alcohol polymer. It is preferably 85 mol % or more and 99.9 mol % or less, more preferably 90 mol % or more and 99.9 mol % or less.

The aforementioned vinyl alcohol polymer having the aforementioned structures (I) and (II) at the polymer ends, the molar ratio of the structure (I) to the total amount of the structures (I) and (II) R[I/(I+II )] preferably satisfy the following formula (1). The molar ratio R[I/(I+II)] preferably satisfies the following formula (1-1), more preferably the following formula (1-2), and particularly preferably the following formula (1-3). The molar ratio R[I/(I+II)] can be adjusted by washing the vinyl alcohol polymer after saponification. On the other hand, the molar ratio R[I/(I+II))] is preferably 0.1 or more. This is because it is difficult to make EVOH less than 0.1 in the industrial manufacturing method, which leads to an increase in manufacturing cost. R＜0.92-Et/100 (1) R＜0.90-Et/100 (1-1) R＜0.88-Et/100 (1-2) R＜0.85-Et/100 (1-3) [In formulae (1) to (1-3), Et is the aforementioned ethylene unit content (mol %). ]

Moreover, the molar ratio R[I/(I+II)] of the structure (I) to the total amount of the structure (I) and the structure (II) preferably satisfies the following formula (2), more preferably the following formula (2-1). 0.8＜R+Et/100 (2) 0.9＜R+Et/100 (2-1) [In formulas (2) and (2-1), Et is the same as above].

In the aforementioned formulas (1) to (1-3), when the molar ratio R[I/(I+II)] does not satisfy the above formula, the water solubility of the ethylene-vinyl alcohol copolymer decreases, or it is used as an adhesive. At this time, the high-speed coatability of the resulting adhesive decreases.

In addition, in the aforementioned formulas (2) and (2-1), the larger value on the right side means that the ratio of the nitrile group derived from the polymerization initiator is converted into the aforementioned cyclic ester structure is high, and the formula (2-1) It means that its ratio is higher. By satisfying the formula (2), the viscosity stability of the vinyl alcohol polymer in the initial stage of melting can be improved, and a rapid increase in the viscosity in the initial stage of melting from 5 minutes to 20 minutes after the start of melting can be suppressed. Such an increase in viscosity can be further suppressed if the formula (2-1) is satisfied.

In the case of the vinyl alcohol polymer obtained by polymerizing the aforementioned vinyl acetate and ethylene of the present invention, the vinyl alcohol polymer having a block characteristic of ethylene units of 0.90 to 0.99 is used for the vinyl alcohol polymer in addition to the easily traceable point of view. In the case of the coating agent, it is preferable from the viewpoints of the viscosity stability of the obtained coating agent and the barrier properties of the obtained coated paper.

The aforementioned block characteristic is a numerical value representing the distribution of vinyl alcohol units resulting from saponification of ethylene units and vinyl ester units, and takes a value between 0 and 2. 0 means that the ethylene units or vinyl alcohol units are completely block distributed, and the interaction increases as the value increases, 1 means that the ethylene units and the vinyl alcohol units are completely random, and 2 means that the ethylene units and the vinyl alcohol units are completely interactive. The aforementioned block characteristics were determined by ¹³ C-NMR in the following manner. First, after the ethylene-vinyl alcohol copolymer was saponified to a degree of saponification of 99.9 mol % or more, it was sufficiently washed with methanol and dried under reduced pressure at 90° C. for 2 days. After dissolving the obtained fully saponified ethylene-vinyl alcohol copolymer in DMSO-d ₆ , the obtained sample was measured at 80°C using ¹³ C-NMR (JEOL GX-500) at 500 MHz. The obtained spectrum was classified according to the method described in T. Moritani and H. Iwasaki, 11, 1251-1259, Macromolecules (1978), and the calculated molar fraction of vinyl alcohol-ethylene 2-unit chain was used The block characteristic (η) of the ethylene unit was obtained from the following formula using the ratio (AE), the molar fraction (A) of the vinyl alcohol unit, and the molar fraction (E) of the ethylene unit. η=(AE)/{2×(A)×(E)}

The ethylene-vinyl ester copolymer having the aforementioned block characteristics can be obtained by using a wide blade in a polymerization tank so that the stirring power Pv per unit volume is 0.5 to 10 kW/m ³ , and the flow number is (Froude number) The solution containing vinyl ester is brought into contact with the ethylene-containing gas while stirring the solution so that Fr is 0.05 to 0.2.

As described above, the vinyl acetate of the present invention has a specific value of ¹⁴ C/C, unlike the conventional vinyl acetate obtained from ethylene and acetic acid derived from petrochemical raw materials. Moreover, it is more preferable that δ ¹³ C has a value different from that of conventional vinyl acetate in addition to ¹⁴ C/C. Therefore, the vinyl acetate of the present invention and the vinyl acetate polymer with vinyl acetate as the monomer unit obtained by polymerizing it, and the vinyl alcohol polymer of its saponification product, have a specific range of ¹⁴ C/ C, and preferably δ ¹³ C within a specific range, can therefore be distinguished from commercially available or conventional vinyl acetate and vinyl acetate polymers obtained by polymerizing them and their saponified products. Therefore, the vinyl acetate polymer and vinyl alcohol polymer obtained by using the vinyl acetate of the present invention can be traced after manufacture or after sale.

The method for tracing vinyl acetate polymer and vinyl alcohol polymer after production is to analyze in advance vinyl acetate polymer and vinyl alcohol polymer which is a saponified product of vinyl acetate as a raw material before polymerization, namely vinyl acetate The ¹⁴ C/C of vinyl acetate polymer or vinyl alcohol polymer recovered after manufacture or after sale is measured, and the result is compared with the pre-measured ¹⁴ C of the raw material vinyl acetate ^. By comparing with /C, it can be determined whether the recovered vinyl acetate polymer or vinyl alcohol polymer is the product of its own company, and if it is a product of its own company, its batch number can be further confirmed. Again, these determinations are made easier by keeping δ ¹³ C in a fixed range.

In addition to the above, the vinyl acetate of the present invention contains at least the above-mentioned acetate, a polymerization inhibitor, a polyhydric alcohol, a hydroxycarboxylic acid, a hydroxylactone-based compound, and an acetaldehyde dimethyl acetal within the above-mentioned range. Either way, it becomes easier to track.

In addition, the vinyl alcohol polymer of the saponified product of vinyl acetate polymer containing the vinyl acetate of the present invention as a monomer unit by polymerizing the vinyl acetate of the present invention contains the aforementioned 1,2-diol bond within the aforementioned range. , the aforementioned polymer terminal has at least any one of a propylidene or alkoxy group, the aforementioned structure (I) and structure (II), and block properties, thereby making it easier to trace, and the resulting vinyl alcohol polymer properties have been modified to suit the intended use.

In addition to measuring ¹⁴ C/C and δ ¹³ C of the product recovered after use, by measuring the aforementioned 1,2-diol bond, whether the aforementioned polymer terminal has a propylidene or alkoxy group, the aforementioned structure, respectively, by the aforementioned methods At least any one of (I), structure (II), and block characteristics can be determined whether the recovered product contains the vinyl alcohol polymer of its own company, and further, its production line can be determined.

As described above, since the raw materials can be traced from the vinyl acetate polymer having the vinyl acetate of the present invention as a monomer unit and the vinyl alcohol polymer of its saponification, it can be polymerized from the vinyl acetate polymer or vinyl alcohol The quality of the resulting molded product is fed back to the quality of the raw material vinyl acetate. In addition, the production line of vinyl acetate polymer or vinyl alcohol polymer and vinyl acetate as raw materials can be easily checked from the molded article.

In addition, in the above description, although substances, conditions, methods, numerical ranges, etc. are illustrated, the present invention is not limited to such illustrations. Specifically, the present invention is not limited to each embodiment, and various modifications can be made within the scope of the claims. For the embodiment obtained by appropriately combining the technical means disclosed in the different embodiments, it also includes within the technical scope of the present invention. In addition, unless otherwise specified, the exemplified substances may be used alone or in combination of two or more. [Example]

The following examples are shown to illustrate the present invention more concretely, but the present invention is not limited to these examples. In addition, the measurement and evaluation in the following examples are based on the following method.

(1) Analysis of vinyl acetate Using a gas chromatograph, what added 1 g of n-propyl acetate as an internal standard to 6 g of the reaction solution was used as an analysis solution. Measurement conditions are as follows.

Device: GC-9A manufactured by Shimadzu Corporation Detector: FID Column: TC-WAX manufactured by GL Sciences Co., Ltd. (length 30 m, inner diameter 0.25 mm, film thickness 0.5 μm) Injection temperature: 200℃ Detector temperature: 200℃ Column temperature: from 45°C (hold for 2 minutes) to 130°C at a temperature increase rate of 4°C/min and held for 15 minutes, then heated to 200°C at a temperature increase rate of 25°C/min and held for 10 minutes.

(2) Measurement of carbon isotope ratio Graphitization was performed by treatment, and the carbon stable isotope ratio (δ ¹³ C) was obtained by an accelerator mass spectrometry method. In addition, the calculation formula is obtained by the above-mentioned formula (3). In addition, as the standard of ¹⁴ C concentration, the graphite synthesized by the oxalic acid standard substance (HOxII) provided by the National Institute of Standards and Technology of the United States was used. The carbon isotope ratios ( ¹⁴ C/ ¹² C ratio, ¹³ C/ ¹² C ratio) of the sample and the standard are measured by accelerator mass spectrometry, and the ¹⁴ C concentration is calculated from these measurement results. Using the ¹⁴ C concentration of the sample obtained by the measurement, the mixing ratio of biomass-derived carbon and petrochemical resource-derived carbon was evaluated for carbon contained in the sample.

(3) Measurement of Sulfur Content The quantitative determination of the sulfur content was performed using a trace nitrogen-sulfur analyzer (TS-2100H type) manufactured by Mitsubishi analytech, and the measurement conditions were as follows. Heater temperature: Inlet 900°C, Outlet 900°C Gas flow: Ar, O ₂ each 300ml/min [Analysis system NSX-2100] Measurement mode: TS Parameter: SD-210 Measurement time (timer): 540 seconds (9 minutes) ) PMT sensitivity: high concentration

(4) Identification of the sulfur component was performed using a gas chromatograph (GC) and a gas chromatograph mass spectrometer (GC/MS). As a detector of GC, FPD (Flame Photometric Detector), which exhibits high sensitivity to trace amounts of sulfur compounds and phosphorus compounds, is used, and it is performed by analyzing the mass components observed during the retention time for detecting the sulfur components. identification.

(5) Saponification degree and average degree of polymerization of vinyl alcohol polymer The methanol solution of polyvinyl acetate obtained by removing the unreacted vinyl acetate monomer after polymerization was saponified at an alkali molar ratio of 0.5, and then pulverized, and the obtained pulverized product was left at 60° C. for 5 hours for saponification. Then, methanol soxhlet was performed for 3 days, followed by drying under reduced pressure at 80°C for 3 days to obtain a purified vinyl alcohol polymer. The degree of saponification and the average degree of polymerization of this refined vinyl alcohol polymer were measured in accordance with JIS K6726:1994.

(6) Ethylene unit content and saponification degree of ethylene-vinyl alcohol copolymer The ethylene-vinyl alcohol copolymer particles were dissolved in dimethylsulfoxide (tetramethylsilane as an internal standard substance and tetrafluoroacetic acid as an additive). DMSO)-d ₆ was measured at 80° C. using ¹ H-NMR at 500 MHz (“JMTC-400/54/SS” manufactured by JEOL Ltd.) to measure the ethylene unit content and the degree of saponification. Each peak in the spectrum measured above is classified in the following manner. 0.6 to 1.9 ppm: methylene protons (4H) of ethylene units, methylene protons (2H) of vinyl alcohol units, methylene protons (2H) of vinyl acetate units 1.9 to 2.0 ppm: vinyl acetate units Methyl protons (3H) 3.1 to 4.2 ppm: methine protons (1H) of vinyl alcohol units

(7) Quantification of carboxylic acid 20 g of ethylene-vinyl alcohol copolymer pellets and 100 mL of ion-exchanged water were put into a 200-mL conical flask with a stopper, a condenser was installed, and the mixture was stirred at 95° C. for 6 hours to perform extraction. The obtained extract was subjected to neutralization titration with an N/50 aqueous sodium hydroxide solution using phenolphthalein as an indicator, and the carboxylic acid content in terms of carboxylate was quantified. In addition, when a phosphorus compound is contained, the content of the phosphorus compound measured by the evaluation method mentioned later is added, and the amount of carboxylic acid is calculated.

(8) Quantification of metal ions, phosphoric acid compounds and borides 0.5 g of ethylene-vinyl alcohol copolymer particles were placed in a pressure vessel made of Teflon (registered trademark), 5 mL of concentrated nitric acid was added thereto, and the mixture was decomposed at room temperature for 30 minutes. After 30 minutes, the lid was closed, and the mixture was decomposed by heating at 150° C. for 10 minutes with a wet decomposition apparatus (“MWS-2” manufactured by ACTAC Corporation) and then at 180° C. for 5 minutes, and then cooled to room temperature. The cooled liquid was transferred to a 50 mL volumetric flask (manufactured by TPX) and filled with pure water. This solution was subjected to elemental analysis using an ICP emission spectrometer (“OPTIMA4300DV” manufactured by PerkinElme), and the metal atom-equivalent amount of the metal ion contained in the ethylene-vinyl alcohol copolymer particles and the phosphorus-atom-equivalent amount of the phosphorus compound were obtained. and the boron-atom equivalent of borides.

(9) Oxygen permeability Using a uniaxial extrusion device (“D2020” manufactured by Toyo Seiki Co., Ltd.; D(mm)=20, L/D=20, compression ratio=3.0, screw: full-scale type), from ethylene-vinyl alcohol copolymer pellets A monolayer film with an average thickness of 20 μm was produced. The respective conditions at this time are as follows. After the obtained film was conditioned under the conditions of 20°C/65%RH, the oxygen permeability was measured under the conditions of 20°C/65%RH using an oxygen permeability measuring device ("OX-Tran2/20" manufactured by Modern Control Corporation). In addition, the measurement system was implemented based on JIS K 7126-2 (isobaric method; 2006) ISO14663-2 annex C. (Conditions of uniaxial extrusion equipment) Extrusion temperature: 210℃ Screw speed: 40rpm Mould width: 30cm Traction drum temperature: 80℃ Traction drum speed: 3.1m/min

(10) Appearance evaluation (10-1) Evaluation of defects in single-layer film production A single-layer film was produced by continuous operation under the same conditions as described above, and the number of defects per 17 cm of film length was calculated for each film produced 5 hours after the start of operation. The calculation of the said number of defects was performed using a film defect inspection apparatus ("AI-10" by Frontier System Co., Ltd.). In addition, the inspection camera in this film defect inspection apparatus was installed so that the lens position might be 195 mm away from the film surface.

(10-2) Coloring evaluation of the end of the reel Five hours after the start of operation, 100 m of the produced film was wound around a paper tube to prepare a roll, and it was visually determined whether or not coloring was caused by yellowing of the roll end.

(11) Amount of 1,2-Diol Bonds A vinyl alcohol polymer was dissolved in dimethylsulfoxide (DMSO)-d ₆ containing tetramethylsilane as an internal standard substance and tetrafluoroacetic acid as an additive, and 500 MHz was used ¹ H-NMR (“JMTC-400/54/SS” manufactured by JEOL Ltd.) was measured at 80°C. The peaks of methine protons derived from vinyl alcohol units were classified as 3.2 to 4.0 ppm (integrated value A), and the peaks of 1 methine protons derived from 1,2-diol bonds were classified as 3.15 to 3.35 ppm In the vicinity (integrated value B), the 1,2-diol bond amount was calculated by the following formula. 1,2-Diol bond amount (mol%)=B/A×100

(12) Content ratio of propyl group at one end of vinyl alcohol polymer The content ratio of propyl group at one end of vinyl alcohol polymer is determined by ¹ H- obtained by NMR. The sample ethylene-modified vinyl ester polymer was purified by reprecipitation three or more times using a mixed solution of n-hexane and acetone, and then dried under reduced pressure at 80° C. for 3 days to prepare an ethylene-modified vinyl ester polymer for analysis. The ethylene-modified vinyl ester polymer for analysis was dissolved in DMSO-d ₆ and measured at 80° C. using ¹ H-NMR at 500 MHz (“JMTC-400/54/SS” manufactured by JEOL Ltd.). Using the peak value of main chain methine protons derived from vinyl acetate (integrated value R: 4.7 to 5.2 ppm) and the peak value of methyl protons derived from propyl group (integrated value S: 0.7 to 1.0 ppm), it was calculated by the following formula Propyl content. Content rate of propyl group (mol%)=100×(S/3)/R

(13) Content of sodium acetate in resin material The content of sodium acetate in the resin material containing the vinyl alcohol polymer as a main component was determined by the dissolution conductivity method described in JIS K 6726:1994.

(14) Solubility of resin materials 90 g of water for 10 g of the resin material, that is, 100 g of a 10% aqueous solution of the resin material, was stirred at 90° C. at 300 rpm for 5 hours, and the whole amount was filtered with a 200-mesh gold mesh. In addition, 200 meshes are equivalent to 75 μm in aperture in the mesh conversion of JIS standard sieves. The pore diameter of the sieve is determined based on the nominal pore diameter W of JIS Z 8801-1-2006. Let the quality of the gold mesh before filtering be a(g). Dry together with gold mesh at 105°C for 3 hours. The total mass of the dried gold mesh and the remaining substances on the gold mesh is set as b(g). The solubility (%) of the resin material was determined using the following formula. Solubility (%)=100-100×{(b-a)/10}

(15) Viscosity stability of aqueous solution of resin material 100 g of a 10% aqueous solution of the resin material prepared under the above conditions was placed at 5°C, and the viscosity c at the time point when the liquid temperature reached 5°C was obtained, and compared with the viscosity d after being left at 5°C for 48 hours, and so on. The ratio of (viscosity ratio) d/c to find out the viscosity stability of the aqueous solution. The larger the value of d/c, the greater the viscosity increase when placed at 5°C, and the worse the viscosity stability. In addition, the viscosity (mPa·s) is a value measured using a B-type viscometer ("BLII" manufactured by Toki Sangyo Co., Ltd.) under the conditions of a rotor rotation number of 60 rpm and a temperature of 20°C.

(16) Hue (YI) of resin material The hue of the resin material is determined from the yellowness index (YI) of the powder. After removing particles smaller than 100 μm and exceeding 1,000 μm using a sieve (pore diameter: 100 μm, 1,000 μm), measurement was performed using a colorimeter (“SM-T-H1” manufactured by Suga Test Instruments Co., Ltd.). In addition, YI is a value measured and calculated in accordance with JIS Z 8722:2009 and JIS K 7373:2006.

(17) Contents of Structures (I) and (II) Vinyl alcohol polymer was dissolved in dimethylsulfoxide (DMSO)-d ₆ containing tetramethylsilane as an internal standard substance and tetrafluoroacetic acid as an additive, The measurement was performed at 45° C. using ¹ H-NMR at 500 MHz (“JMTC-400/54/SS” manufactured by JEOL Ltd.). The structure was obtained from the ratio of the peak intensity of the ethylene unit, vinyl alcohol unit, and vinyl ester unit to the peak intensity of the methyl hydrogen of the methoxy group or the methylene hydrogen of the ethoxy group contained in the structures (I) and (II). (I), (II) content. In addition, the peaks of the methyl hydrogen of the methoxy group or the methylene hydrogen of the ethoxy group which the structure (I) has, and the peaks of the methoxy group of the structure (II) were detected at around 3.07 ppm and 3.09 ppm, respectively. Peaks of methyl hydrogen or methylene hydrogen of ethoxy.

(18) Block properties of ethylene units of ethylene-vinyl alcohol copolymer The ethylene-vinyl alcohol copolymer was dissolved in dimethylsulfoxide (DMSO)-d ₆ containing tetrafluoroacetic acid as an additive, and ¹³ C at 500 MHz was used. -NMR ("JMTC-400/54/SS" by JEOL Ltd.) was measured at 80 degreeC. The obtained spectrum was classified according to the method described in T. Moritani and H. Iwasaki, 11, 1251-1259, Macromolecules (1978), and the calculated molar fraction ( AE), the molar fraction (A) of the vinyl alcohol unit, and the molar fraction (E) of the ethylene unit, and the block characteristic (η) of the ethylene unit was obtained by the following formula. η=(AE)/{2×(A)×(E)}

<Synthesis example 1: Preparation of vinyl acetate synthetic catalyst> The silica sphere carrier was impregnated with an aqueous solution containing an aqueous solution of sodium tetrachloropalladate and an aqueous solution of tetrachloroauric acid tetrahydrate with an amount of water absorbed by the carrier, and then immersed in an aqueous solution containing sodium metasilicate 9 hydrate and left to stand . Then, a hydrazine hydrate aqueous solution was added, and after standing at room temperature, it was washed with water until the chloride ion disappeared in the water, and then dried. The palladium/gold/support composition was immersed in an aqueous acetic acid solution and left to stand. It is then washed with water and then dried. After that, it was immersed in an aqueous solution corresponding to the amount of water absorbed by the carrier of potassium acetate, and dried to obtain a vinyl acetate synthetic catalyst.

<Synthesis example 2: Production of straw-derived bioethylene> Using the straw of C3 plant as a raw material, it is processed through an alkali treatment step, a saccharification treatment step, and an ethanolization step, thereby obtaining biomass ethanol. This biomass ethanol was subjected to a dehydration reaction treatment at 190° C. using mordenite as a catalyst, whereby biomass ethylene derived from C3 plants was obtained.

<Synthesis example 3: Production of straw-derived bioacetic acid> The biomass ethanol obtained in Synthesis Example 2 was oxidized to obtain biomass acetic acid derived from C3 plants.

<Example 1> The catalyst obtained in Synthesis Example 1 was diluted with glass beads, filled into a reaction tube made of SUS, and a mixed gas of ethylene, oxygen, water, acetic acid, and nitrogen was poured into the reaction tube for reaction. As the ethylene system, biomass ethylene (manufactured by Braskem SA) derived from sugarcane which is a C4 plant was used. In addition, the acetic acid system vaporizes biomass acetic acid derived from sugar cane which is a C4 plant, and is introduced into the reaction system as a vapor. The reaction outlet gas was analyzed to obtain the yield and selectivity of vinyl acetate. The obtained vinyl acetate was analyzed by the aforementioned method, and ¹⁴ C/C and δ ¹³ C and sulfur content were measured. The obtained vinyl acetate was designated as VAM-1, and the results are shown in Table 1.

<Example 2> The reaction was carried out in the same manner as in Example 1, except that all the biomass acetic acid was changed to petroleum-derived acetic acid. The reaction outlet gas was analyzed to obtain the yield and selectivity of vinyl acetate. The obtained vinyl acetate was analyzed by the aforementioned method, and ¹⁴ C/C and δ ¹³ C and sulfur content were measured. The obtained vinyl acetate was designated as VAM-2, and the results are shown in Table 1.

<Example 3> The reaction was carried out in the same manner as in Example 1, except that half of the biomass ethylene was changed to petroleum-derived ethylene, and all of the biomass acetic acid was changed to petroleum-derived acetic acid. The reaction outlet gas was analyzed to obtain the yield and selectivity of vinyl acetate. The obtained vinyl acetate was analyzed by the aforementioned method, and ¹⁴ C/C and δ ¹³ C and sulfur content were measured. The obtained vinyl acetate was designated as VAM-3, and the results are shown in Table 1.

<Example 4> Except that the biomass ethylene was all changed to the C3 plant-derived ethylene obtained in the synthesis example 2, and the biomass acetic acid was changed to the C3 plant-derived acetic acid obtained in the synthesis example 3, The reaction was carried out in the same manner as in Example 1. The reaction outlet gas was analyzed to obtain the yield and selectivity of vinyl acetate. The obtained vinyl acetate was analyzed by the aforementioned method, and ¹⁴ C/C and δ ¹³ C and sulfur content were measured. The obtained vinyl acetate was referred to as VAM-4, and the results are shown in Table 1.

<Example 5> The same procedure as in Example 1 was carried out, except that all biomass ethylene was changed to the C3 plant-derived ethylene obtained in Synthesis Example 2, and all biomass acetic acid was changed to petroleum-derived acetic acid. reaction. The reaction outlet gas was analyzed to obtain the yield and selectivity of vinyl acetate. The obtained vinyl acetate was analyzed by the aforementioned method, and ¹⁴ C/C and δ ¹³ C and sulfur content were measured. The obtained vinyl acetate was designated as VAM-5, and the results are shown in Table 1.

<Example 6> Half of the biomass ethylene was changed to C3 plant-derived ethylene obtained in Synthesis Example 2, the remaining half was changed to petroleum-derived ethylene, and all biomass acetic acid was changed to the source. The reaction was carried out in the same manner as in Example 1, except that the petroleum-derived acetic acid was used. The reaction outlet gas was analyzed to obtain the yield and selectivity of vinyl acetate. The obtained vinyl acetate was analyzed by the aforementioned method, and ¹⁴ C/C and δ ¹³ C and sulfur content were measured. The obtained vinyl acetate was designated as VAM-6, and the results are shown in Table 1.

<Comparative Example 1> The reaction was carried out in the same manner as in Example 1, except that all of the biomass ethylene was changed to petroleum-derived ethylene, and all of the biomass acetic acid was changed to petroleum-derived acetic acid. The reaction outlet gas was analyzed to obtain the yield and selectivity of vinyl acetate. The obtained vinyl acetate was analyzed by the aforementioned method, and ¹⁴ C/C and δ ¹³ C and sulfur content were measured. The obtained vinyl acetate was designated as VAM-C1, and the results are shown in Table 1.

Table 1 vinyl Acetic acid Space-time yield [g/L-catalyst·hour] Selectivity [%] ¹⁴ C/C [-] δ ¹³ C [‰] S [ppm] Example 1 100% derived from sugar cane (C4 plant) 100% derived from sugar cane (C4 plant) 746 90.0 9.5× ^10-13 -12 1.2 Example 2 100% derived from sugar cane (C4 plant) 100% derived from petroleum 749 90.3 5.0× ^10-13 -20 0.7 Example 3 50% from sugar cane (C4 plant) / 50% from petroleum 100% derived from petroleum 747 90.1 2.4× ^10-13 -twenty two 0.3 Example 4 100% derived from straw (C3 plant) 100% derived from straw (C3 plant) 748 90.2 9.5× ^10-13 -38 1.0 Example 5 100% derived from straw (C3 plant) 100% derived from petroleum 745 90.2 5.1× ^10-13 -32 0.6 Example 6 50% from straw (C3 plant) / 50% from petroleum 100% derived from petroleum 746 90.0 2.5× ^10-13 -28 0.3 Comparative Example 1 100% derived from petroleum 100% derived from petroleum 749 90.3 <1.0× ^10-14 -25 <0.01 In Table 1, S is the content of the sulfur component in vinyl acetate. In addition, vinyl acetate obtained by the method described in Examples 1 to 6 contains dimethyl sulfide and/or dimethyl sulfoxide as sulfur components.

<Reference Example 1> To the vinyl acetate (VAM-1) obtained in Example 1, 3 ppm of hydroquinone was added as a polymerization inhibitor.

<Reference Example 2> To the vinyl acetate (VAM-1) obtained in Example 1, 15 ppm of hydroquinone was added as a polymerization inhibitor.

<Example 7> 720 parts by mass of vinyl acetate (VAM-1) obtained in Example 1 and 280 parts by mass of methanol were added to a reactor equipped with a stirrer, a reflux cooling pipe, a nitrogen gas introduction pipe, and an addition port for a polymerization initiator, Nitrogen substitution was performed in the system for 30 minutes while nitrogen bubbling was performed. The temperature rise of the reactor was started, and when the internal temperature reached 60°C, 0.13 parts by mass of 2,2'-azobisisobutyronitrile was added to start the polymerization. After 3 hours of polymerization at 60°C, cooling was performed to stop the polymerization. Then, unreacted vinyl acetate was removed while adding methanol from time to time under reduced pressure at 30° C. to obtain a methanol solution of a vinyl acetate polymer. Next, 9.2 parts by mass of a methanol solution having a sodium hydroxide concentration of 10 mass % was added to the methanol solution of the vinyl acetate polymer prepared by further adding methanol to this methanol solution, and saponification was performed at 40°C. About 15 minutes after adding the methanol solution of sodium hydroxide, a gelatinous substance was formed, so it was pulverized with a pulverizer and left at 40° C. for 1 hour for saponification. Then, 500 parts of methyl acetate was added, and the remaining alkali was added to and. After confirming completion of neutralization using a phenolphthalein indicator, filtration was performed to obtain a white solid. 2,000 parts of methanol was added to this white solid, and it was left to stand at room temperature for 3 hours, and then washed. After repeating this washing operation three times, centrifugal deliquoring was performed, and the obtained white solid was heat-treated at 120° C. for 4.5 hours in a dryer to obtain a vinyl alcohol polymer (PVOH-1). The physical properties of PVOH-1 are shown in Table 2.

<Example 8> A vinyl alcohol polymer (PVOH-2) was obtained by carrying out the reaction in the same manner as in Example 7 except that all the vinyl acetates were changed to VAM-2. The physical properties of PVOH-2 are shown in Table 2.

<Example 9> A vinyl alcohol polymer (PVOH-3) was obtained by carrying out the reaction in the same manner as in Example 7, except that all the vinyl acetates were changed to VAM-3. The physical properties of PVOH-3 are shown in Table 2.

<Example 10> A vinyl alcohol polymer (PVOH-4) was obtained by carrying out the reaction in the same manner as in Example 7, except that the half amount of vinyl acetate was changed to VAM-1 and the remaining half amount was changed to VAM-C1. The physical properties of PVOH-4 are shown in Table 2.

<Example 11> A vinyl alcohol polymer (PVOH-5) was obtained by carrying out the reaction in the same manner as in Example 7 except that all the vinyl acetates were changed to VAM-4. The physical properties of PVOH-5 are shown in Table 2.

<Example 12> A vinyl alcohol polymer (PVOH-6) was obtained by carrying out the reaction in the same manner as in Example 7 except that all the vinyl acetates were changed to VAM-5. The physical properties of PVOH-6 are shown in Table 2.

<Example 13> A vinyl alcohol polymer (PVOH-7) was obtained by carrying out the reaction in the same manner as in Example 7 except that all the vinyl acetates were changed to VAM-6. The physical properties of PVOH-7 are shown in Table 2.

<Example 14> A vinyl alcohol polymer (PVOH-8) was obtained by carrying out the reaction in the same manner as in Example 7, except that the half amount of vinyl acetate was changed to VAM-4 and the remaining half amount was changed to VAM-C1. The physical properties of PVOH-8 are shown in Table 2.

<Comparative Example 2> A vinyl alcohol polymer (PVOH-C1) was obtained by carrying out the reaction in the same manner as in Example 4 except that all the vinyl acetates were changed to VAM-C1. The physical properties of PVOH-C1 are shown in Table 1.

Table 2 vinyl acetate Viscosity Average Degree of Polymerization Saponification degree [mol%] Surface tension of 0.1% aqueous solution [dyne/cm] ¹⁴ C/C [-] δ ¹³ C [‰] Example 7 VAM-1 1,616 99.6 64.7 9.5× ^10-13 -12 Example 8 VAM-2 1,626 99.7 64.9 9.5× ^10-13 -13 Example 9 VAM-3 1,650 99.7 65.3 5.0× ^10-13 -19 Example 10 VAM-1/VAM-C1=50/50 1,630 99.6 64.9 5.0× ^10-13 -20 Example 11 VAM-4 1,620 99.7 64.9 9.5× ^10-13 -38 Example 12 VAM-5 1,642 99.7 65.2 9.5× ^10-13 -38 Example 13 VAM-6 1,631 99.6 64.8 5.0× ^10-13 -32 Example 14 VAM-4/VAM-C1=50/50 1,628 99.7 64.7 5.0× ^10-13 -31 Comparative Example 2 VAM-C1 1,690 99.7 65.2 <1.0× ^10-14 -25

As is clear from Table 2 above, even vinyl acetates having different ¹⁴ C/C and δ ¹³ C can obtain vinyl alcohol polymers with the same physical properties as long as they are polymerized and saponified under the same conditions.

<Example 15> (Production of Ethylene Vinyl Acetate Copolymer) 105 kg of VAM-1 and 32.3 kg of methanol were supplied to a 250 L pressurized reaction tank equipped with a jacket, agitator, nitrogen introduction port, ethylene introduction port, and starter addition port, and the temperature was raised to 65°C, followed by nitrogen bubbling for 30 minutes. , for nitrogen substitution in the reaction tank. Next, ethylene was raised and introduced so that the pressure of the reaction tank (ethylene pressure) would be 3.67 MPa. As the ethylene system, sugarcane-derived ethylene (manufactured by Braskem S.A.) was used. After adjusting the temperature in the reaction tank to 65°C, 16.8 g of 2,2'-azobis(2,4-dimethylvaleronitrile) was added as a methanol solution as an initiator to start polymerization. During the polymerization, the ethylene pressure was maintained at 3.67 MPa, and the polymerization temperature was maintained at 65°C. When the polymerization rate of vinyl acetate became 45% after 3 hours, cooling was performed to stop the polymerization. After the reaction tank was opened for deethylene, nitrogen was bubbled to complete deethylene. Next, after removing unreacted vinyl acetate under reduced pressure, methanol was added to the obtained ethylene-vinyl acetate copolymer as a 20 mass % methanol solution.

(Saponification and cleaning) 250 kg of a 20 mass % methanol solution of the obtained ethylene-vinyl acetate copolymer was put into a 500 L reaction tank equipped with a jacket, a stirrer, a nitrogen gas inlet, a reflux cooler, and a solution addition port, and nitrogen gas was blown into the solution. The temperature was raised to 60°C, and 4 kg of sodium hydroxide as a methanol solution with a concentration of 2N was added. After the addition of sodium hydroxide was completed, the temperature in the system was maintained at 60° C. and the mixture was stirred for 2 hours to carry out the saponification reaction. After 2 hours, 4 kg of sodium hydroxide was added again in the same manner, and heating and stirring were continued for 2 hours. After that, 14 kg of acetic acid was added to stop the saponification reaction, and 50 kg of ion-exchanged water was added. Methanol and water were distilled out of the reaction tank while heating and stirring, and the reaction liquid was concentrated. After 3 hours, 50 kg of ion-exchanged water was further added to precipitate the ethylene-vinyl alcohol copolymer. The ethylene-vinyl alcohol copolymer precipitated by decantation was collected and pulverized with a mixer. The obtained ethylene-vinyl alcohol copolymer (EVOH-1) powder was put into an acetic acid aqueous solution obtained by adding 1 L of water (1 g/L) to 1 g of acetic acid (bath ratio 20, 10 kg of powder to 200 L of ion-exchanged water). ratio), stirred for 2 hours for cleaning. This was deliquored, 1 g/L of acetic acid aqueous solution (bath ratio 20) was added, and the mixture was stirred for 2 hours for washing. The deliquored product was put into ion-exchanged water (bath ratio 20), stirred and washed for 2 hours, and then deliquored. This operation was repeated three times for purification. This was dried at 60°C for 16 hours, whereby a crude dried product of EVOH-1 was obtained.

(Manufacture of water-containing pellets) 25 kg of the obtained crude dried product of EVOH-1 was put into a 100 L stirring tank equipped with a jacket, a stirrer and a reflux cooler, 20 kg of water and 20 g of methanol were added, and the temperature was raised to 70° C. to dissolve. The solution was passed through a glass tube with a diameter of 3 mm, cooled to 5° C. to become a mixed solution of water/methanol=90/10 in mass ratio, extruded to precipitate into strands, and cut with strands The strand was cut into granules with a knife, thereby obtaining hydrated granules of EVOH-1. This EVOH-1 water-containing pellet was put into an acetic acid aqueous solution with a concentration of 1 g/L (bath ratio 20) to perform stirring and washing for 2 hours. This was deliquored, 1 g/L acetic acid aqueous solution (bath ratio 20) was added, and the mixture was stirred and washed for 2 hours. After deliquoring, the acetic acid aqueous solution was renewed and the same operation was performed. After washing with an aqueous acetic acid solution and deliquoring, the product was put into ion-exchanged water (bath ratio 20), stirred and washed for 2 hours, and then deliquored. The methanol used in the precipitation of strands was used to obtain EVOH-1 water-containing particles. The moisture content of the obtained EVOH-1 water-containing particles was measured with a halogen moisture meter "HR73" from Mettler.

(Manufacture of pellets) The obtained EVOH-1 water-containing pellets were put into an aqueous solution (bath ratio 20) containing sodium acetate, acetic acid, phosphoric acid, and boric acid, and immersed for 4 hours while regularly stirring. In addition, the concentration of each component was adjusted so that the content of each component in the obtained EVOH-1 pellets was as described in Table 3. After the immersion, the solution was deliquored and dried in air at 80° C. for 3 hours and in air at 130° C. for 7.5 hours to obtain EVOH-1 particles containing sodium acetate, acetic acid, phosphoric acid, and boric acid. The physical properties are shown in Table 3.

<Example 16> The reaction was carried out in the same manner as in Example 15, except that all the vinyl acetates were changed to VAM-2 to obtain ethylene-vinyl alcohol copolymer (EVOH-2) pellets. The physical properties are shown in Table 3.

<Example 17> The reaction was carried out in the same manner as in Example 15, except that all the vinyl acetates were changed to VAM-3 to obtain ethylene-vinyl alcohol copolymer (EVOH-3) pellets. The physical properties are shown in Table 3.

<Example 18> A reaction was carried out in the same manner as in Example 15, except that half the amount of vinyl acetate was changed to VAM-1 and the remaining half amount was changed to VAM-C1 to obtain an ethylene-vinyl alcohol copolymer (EVOH-4) particles. The physical properties are shown in Table 3.

<Example 19> The reaction was carried out in the same manner as in Example 15 except that all the ethylene was changed to petroleum-derived ethylene to obtain ethylene-vinyl alcohol copolymer (EVOH-5) particles. The physical properties are shown in Table 3.

<Example 20> The reaction was carried out in the same manner as in Example 15, except that the half amount of ethylene was changed to petroleum-derived ethylene to obtain ethylene-vinyl alcohol copolymer (EVOH-6) particles. The physical properties are shown in Table 3.

<Example 21> The ethylene-vinyl alcohol copolymer (EVOH-7) pellet was obtained by carrying out the reaction in the same manner as in Example 15, except that all the ethylene was changed to ethylene derived from straw, and all the vinyl acetate was changed to VAM-4. The physical properties are shown in Table 3.

<Example 22> The reaction was carried out in the same manner as in Example 15, except that all of the ethylene was changed to ethylene derived from straw, and all of the vinyl acetate was changed to VAM-5 to obtain ethylene-vinyl alcohol copolymer (EVOH-8) pellets. The physical properties are shown in Table 3.

<Example 23> The reaction was carried out in the same manner as in Example 15, except that all ethylene was changed to ethylene derived from straw, and all vinyl acetate was changed to VAM-6 to obtain ethylene-vinyl alcohol copolymer (EVOH-9) pellets. The physical properties are shown in Table 3.

<Example 24> The reaction was carried out in the same manner as in Example 15, except that all the ethylene was changed to ethylene derived from straw, half of the vinyl acetate was changed to VAM-6, and the remaining half was changed to VAM-C1. Ethylene-vinyl alcohol copolymer (EVOH-10) particles. The physical properties are shown in Table 3.

<Example 25> The reaction was carried out in the same manner as in Example 15, except that all ethylene was changed to petroleum-derived ethylene and all vinyl acetate was changed to VAM-4 to obtain ethylene-vinyl alcohol copolymer (EVOH-11) particles. The physical properties are shown in Table 3.

<Example 26> The same procedure as in Example 15 was carried out, except that half of the ethylene was changed to straw-derived ethylene, the remaining half was changed to petroleum-derived ethylene, and all vinyl acetate was changed to VAM-4. The reaction was carried out to obtain ethylene-vinyl alcohol copolymer (EVOH-12) particles. The physical properties are shown in Table 3.

<Comparative Example 3> The reaction was carried out in the same manner as in Example 8, except that all vinyl acetates were changed to VAM-C1 and all ethylenes were changed to petroleum-derived ethylene to obtain ethylene-vinyl alcohol copolymer (EVOH-C1) particles. The physical properties are shown in Table 3.

table 3 raw material EVOH Granules Evaluation vinyl vinyl acetate Ethylene unit content degree of saponification Carboxylic acid content Metal ion content Phosphate content boron compound content ¹⁴ C/C δ ¹³ C Oxygen permeability mol% mol% ppm ppm ppm ppm - ‰ mL/(m ² ･day･atm) Example 15 100% derived from sugar cane (C4 plant) VAM-1 32 >99 250 200 10 700 9.5× ^10-13 -12 0.3 Example 16 100% derived from sugar cane (C4 plant) VAM-2 32 >99 250 200 10 700 9.5× ^10-13 -13 0.3 Example 17 100% derived from sugar cane (C4 plant) VAM-3 32 >99 250 200 10 700 6.6× ^10-13 -17 0.3 Example 18 100% derived from sugar cane (C4 plant) VAM-1/VAM-C1=50/50 32 >99 250 200 10 700 6.6× ^10-13 -16 0.3 Example 19 100% derived from petroleum VAM-1 32 >99 250 200 10 700 6.8× ^10-13 -16 0.3 Example 20 50% from sugar cane (C4 plant) / 50% from petroleum VAM-1 32 >99 250 200 10 700 8.4× ^10-13 -14 0.3 Example 21 100% derived from straw (C3 plant) VAM-4 32 >99 250 200 10 700 9.5× ^10-13 -38 0.3 Example 22 100% derived from straw (C3 plant) VAM-5 32 >99 250 200 10 700 9.5× ^10-13 -39 0.3 Example 23 100% derived from straw (C3 plant) VAM-6 32 >99 250 200 10 700 6.6× ^10-13 -34 0.3 Example 24 100% derived from straw (C3 plant) VAM-4/VAM-C1=50/50 38 >99 250 200 10 700 6.6× ^10-13 -33 0.3 Example 25 100% derived from petroleum VAM-4 38 >99 250 200 10 700 6.8× ^10-13 -41 0.3 Example 26 50% from straw (C3 plant) / 50% from petroleum VAM-4 32 >99 250 200 10 700 8.4× ^10-13 -36 0.3 Comparative Example 3 100% derived from petroleum VAM-C1 32 >99 250 200 10 700 <1.0× ^10-14 -25 0.3

The ¹⁴ C/C and δ ¹³ C of the previously obtained EVOH-1 to EVOH-6 and EVOH-C1 were measured by the aforementioned methods. The values were approximately the same as the values of ¹⁴ C/C and δ ¹³ C of the vinyl acetate and ethylene used. Furthermore, the ¹⁴ C/C and δ ¹³ C of EVOH-1 to EVOH- ⁶ are different from EVOH-C1, which is all polymerized from petroleum-derived vinyl acetate. C and δ ¹³ C can be specified as raw materials. Thus, ethylene-vinyl acetate alcohol copolymers can be traced.

As shown in Table 3, the EVOH compositions of Examples 15 to 26 have high oxygen barrier properties not inferior to those derived only from petrochemical resources (EVOH composition of Comparative Example 3), although some of them use plant-derived raw materials. .

<Example 27> Except having added 500 ppm of methyl acetate to vinyl acetate, the reaction was carried out in the same manner as in Example 15 to obtain ethylene-vinyl alcohol copolymer (EVOH-13) pellets. Comparing the physical properties of EVOH-1 and EVOH-13, EVOH-13 improves the defects of film forming and the coloring of the end of the roll. At this time, no difference was observed between EVOH-1 and EVOH-13 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 28> The reaction was carried out in the same manner as in Example 15, except that 350 ppm of ethyl acetate was added to vinyl acetate, and the polymerization solvent was changed from methanol to ethanol to obtain an ethylene-vinyl alcohol copolymer (EVOH-14 ) particles. Comparing the physical properties of EVOH-1 and EVOH-14, EVOH-14 improves film-forming defects and coloration at the end of the roll. At this time, no difference was observed between EVOH-1 and EVOH-14 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 29> Except that 500 ppm of methyl acetate was added to vinyl acetate, the reaction was carried out in the same manner as in Example 21 to obtain ethylene-vinyl alcohol copolymer (EVOH-15) particles. Comparing the physical properties of EVOH-1 and EVOH-15, EVOH-15 improves film-forming defects and coloration at the end of the roll. At this time, no difference was observed between EVOH-1 and EVOH-15 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 30> The reaction was carried out in the same manner as in Example 21, except that 350 ppm of ethyl acetate was added to vinyl acetate, and the polymerization solvent was changed from methanol to ethanol to obtain an ethylene-vinyl alcohol copolymer (EVOH-16 ) particles. Comparing the physical properties of EVOH-7 and EVOH-16, EVOH-16 improves film-forming defects and roll end coloration. At this time, no difference was observed between EVOH-7 and EVOH-16 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 31> Except having added 50 ppm of L-ascorbic acid to vinyl acetate, the reaction was carried out in the same manner as in Example 15 to obtain ethylene-vinyl alcohol copolymer (EVOH-17) particles. As a result of the physical properties of EVOH-1 and EVOH-17, EVOH-17 improves film-making defects and coloration at the end of the roll. At this time, no difference was observed between EVOH-1 and EVOH-17 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 32> Except that 50 ppm of erythorbic acid was added to vinyl acetate, the reaction was carried out in the same manner as in Example 15 to obtain ethylene-vinyl alcohol copolymer (EVOH-18) particles. Comparing the physical properties of EVOH-1 and EVOH-18, EVOH-18 improves film-forming defects and coloration at the end of the roll. At this time, no difference was observed between EVOH-1 and EVOH-17 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 33> The reaction was carried out in the same manner as in Example 15, except that 50 ppm of glucono-δ-lactone was added to vinyl acetate to obtain ethylene-vinyl alcohol copolymer (EVOH-19) particles. Comparing the physical properties of EVOH-1 and EVOH-19, EVOH-19 improves film-forming defects and coloration at the end of the roll. At this time, no difference was observed between EVOH-1 and EVOH-19 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 34> Except having added 50 ppm of L-ascorbic acid to vinyl acetate, the reaction was carried out in the same manner as in Example 21 to obtain ethylene-vinyl alcohol copolymer (EVOH-20) particles. Comparing the physical properties of EVOH-7 and EVOH-20, EVOH-20 improves the defects of film forming and the coloring of the end of the roll. At this time, no difference was observed between EVOH-7 and EVOH-20 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

<Example 35> Except having added 50 ppm of erythorbic acid to vinyl acetate, the reaction was carried out in the same manner as in Example 21 to obtain ethylene-vinyl alcohol copolymer (EVOH-21) particles. Comparing the physical properties of EVOH-7 and EVOH-21, EVOH-21 improves film-forming defects and coloration at the end of the roll. At this time, no difference was observed between EVOH-7 and EVOH-21 in ¹⁴ C/C, δ ¹³ C and oxygen permeability.

<Example 36> The reaction was carried out in the same manner as in Example 21, except that 50 ppm of glucono-δ-lactone was added to vinyl acetate to obtain ethylene-vinyl alcohol copolymer (EVOH-22) particles. Comparing the physical properties of EVOH-7 and EVOH-22, EVOH-22 improves film-forming defects and coloration at the end of the roll. At this time, no difference was observed between EVOH-1 and EVOH-22 in ¹⁴ C/C, δ ¹³ C, and oxygen permeability.

From Examples 15, 21, and 31 to 36, the vinyl acetate of the present invention was used, and vinyl acetate alone or in the coexistence of a polyvalent carboxylic acid, a hydroxycarboxylic acid, a hydroxylactone-based compound and a polymerization initiator was further used. Polymerization with other monomers, especially if vinyl acetate and ethylene are copolymerized, the resulting ethylene-vinyl acetate copolymer is useful as a raw material for ethylene-vinyl acetate copolymer saponification. The obtained ethylene-vinyl acetate copolymer saponified product can suppress fisheye during film formation and has excellent hue.

<Example 37> Except having added 0.5 mass part of acetaldehyde dimethyl acetal to vinyl acetate, it carried out the same reaction as Example 7, and obtained the vinyl alcohol polymer (PVOH-9). As a result of visually confirming PVOH-1 and PVOH-9, PVOH-9 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-1 and PVOH-9.

<Example 38> Except having added 4 mass parts of acetaldehyde dimethyl acetal with respect to vinyl acetate, it carried out the same reaction as Example 7, and obtained the vinyl alcohol polymer (PVOH-10). As a result of visually confirming PVOH-1 and PVOH-10, PVOH-10 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-1 and PVOH-10.

<Example 39> Except that 4 parts by mass of acetaldehyde dimethyl acetal and 5 ppm of citric acid were added to vinyl acetate, the reaction was carried out in the same manner as in Example 7 to obtain a vinyl alcohol polymer (PVOH-11 ). As a result of visually confirming PVOH-1 and PVOH-11, PVOH-11 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-1 and PVOH-11.

<Example 40> Except having added 4 parts by mass of acetaldehyde dimethyl acetal and 10 ppm of citric acid to vinyl acetate, the reaction was carried out in the same manner as in Example 7 to obtain a vinyl alcohol polymer (PVOH-12 ). As a result of visually confirming PVOH-1 and PVOH-12, PVOH-12 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-1 and PVOH-12.

<Example 41> Except having added 0.5 mass part of acetaldehyde dimethyl acetal to vinyl acetate, it carried out the same reaction as Example 11, and obtained the vinyl alcohol polymer (PVOH-13). As a result of visually confirming PVOH-5 and PVOH-13, PVOH-13 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-5 and PVOH-13.

<Example 42> Except having added 4 mass parts of acetaldehyde dimethyl acetal to vinyl acetate, it carried out similarly to Example 11, and obtained the vinyl alcohol polymer (PVOH-14). As a result of visually confirming PVOH-5 and PVOH-14, PVOH-14 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-5 and PVOH-14.

<Example 43> Except having added 4 parts by mass of acetaldehyde dimethyl acetal and 5 ppm of citric acid to vinyl acetate, the reaction was carried out in the same manner as in Example 11 to obtain a vinyl alcohol polymer (PVOH-15 ). As a result of visually confirming PVOH-5 and PVOH-15, PVOH-13 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-5 and PVOH-15.

<Example 44> Except having added 4 parts by mass of acetaldehyde dimethyl acetal and 10 ppm of citric acid to vinyl acetate, the reaction was carried out in the same manner as in Example 11 to obtain a vinyl alcohol polymer (PVOH-15 ). When PVOH-5 and PVOH-15 were visually confirmed, PVOH-13 was relatively white and had an excellent hue. At this time, no difference was observed between ¹⁴ C/C and δ ¹³ C between PVOH-5 and PVOH-15.

From Examples 7, 14, and 37 to 44, since vinyl acetate to which acetaldehyde dimethyl acetal was added was used, a vinyl acetate polymer with good quality was obtained, and this polymer was also used for The raw material of vinyl alcohol polymer with excellent hue is obtained.

<Example 45> A continuous polymerization tank equipped with a reflux cooler, a raw material supply line, a reaction liquid extraction line, a thermometer, a nitrogen introduction port, an ethylene introduction port, and a stirring blade was used. Using quantitative pump respectively, with 671L/hr VAM-1, with 148L/hr methanol, with 1.0L/hr the 1% methanol solution of n-propyl peroxydicarbonate as initiator is continuously supplied to the continuous polymerization tank . The addition amount of n-propyl peroxydicarbonate was 0.00132 mass % with respect to VAM-1. The ethylene pressure in the continuous polymerization tank was adjusted to 0.23 MPa. As the ethylene system, sugarcane-derived ethylene (manufactured by Braskem S.A.) was used. The polymerization liquid was continuously taken out from the continuous polymerization tank so that the liquid level in the continuous polymerization tank was fixed. It adjusted so that the polymerization rate of the exit of a continuous polymerization tank might become 26%. At this time, propane as a chain transfer agent was continuously added so that the concentration in the system would be 0.00042 mass % with respect to VAM-1 (the concentration relative to the vinyl acetate remaining in the continuously drawn-out polymerization solution being 100). Thiol. The residence time of the continuous polymerization tank was 5 hours. The temperature at the outlet of the continuous polymerization tank was 60°C. The polymerization solution was recovered from the continuous polymerization tank, and methanol vapor was introduced into the polymerization solution while heating to 75°C in a warm water bath to remove residual vinyl acetate to obtain an ethylene-modified vinyl ester polymer (hereinafter sometimes referred to as EVAc) methanol solution (EVAc concentration 32%). The average residence time in the removal step was 2 hours, and the residual vinyl acetate in the methanol solution of the obtained ethylene-modified vinyl ester polymer was 0.1%.

Then, at 40° C., the water content supplied to the saponification step was 0.5%, and the saponification reaction was performed for 1 hour using sodium hydroxide as a saponification catalyst in a molar ratio of 0.012 to the ethylene-modified vinyl ester polymer. The obtained polymer was immersed in methanol for washing. The solvent was removed by centrifugation, followed by drying, to obtain a calculation with an ethylene unit content of 2 mol %, a viscosity average polymerization degree of 1,700, a saponification degree of 98.5 mol %, and a 1,2-diol bond amount of A composition containing 1.6 mol % of ethylene-vinyl alcohol copolymer (EVOH-23) and a propyl content of 0.0061 mol % at one end as a main component and a content of sodium acetate of 0.42 mass %.

Using the obtained composition, the solubility of EVOH-23 after being heated at 90° C. for 5 hours, the viscosity stability of the aqueous solution, and the hue were measured. Solubility, viscosity stability of aqueous solution, and hue (YI) are good.

<Example 46> FIG. 1 shows the schematic diagram of the polymerization apparatus used, and FIG. 2 shows the schematic diagram of the stirring blade. In a substantially cylindrical polymerization tank 1 [capacity: 7,000 L, tank inner diameter D: 1.8 m], ethylene was introduced from conduit 5 so that the ethylene pressure in the tank was 0.23 MPa, and 2 and 2' of the polymerization initiator were introduced from conduit 6 at a rate of 3 L/hr. - 1 mass % methanol solution of azobis-(4-methoxy-2,4-dimethylvaleronitrile). As the ethylene system, sugarcane-derived ethylene (manufactured by Braskem SA) was used. Further, a liquid containing VAM-1 (VAM-1: 777 L/hr, methanol: 170 L/hr) was introduced into the polymerization tank 1 through the introduction pipe 10 and the heat exchanger 2 . Furthermore, the ethylene-containing gas is introduced into the heat exchanger 2 through the conduit 3 from the polymerization tank 1 . The liquid containing VAM-1 flows down the surface of the tube, thereby absorbing ethylene, and is injected into the polymerization tank 1 through the conduit 4, mixed with the reaction liquid, and provided for continuous polymerization with ethylene. The polymerization liquid was continuously taken out from the conduit 9 so that the liquid level in the polymerization tank 1 was fixed. It adjusted so that the polymerization rate of VAM-1 in the exit of the polymerization tank 1 might become 30%. Moreover, it adjusted so that the stirring power Pv per unit volume might become 2.2 kW/m< ³ >, and the flow number Fr might become 0.13. The reaction solution was stirred in a state in which the entire blade (paddle) was immersed in the reaction solution and the liquid surface was close to the upper end of the blade (paddle). The residence time of the reaction liquid in the polymerization tank was 5 hours. The temperature at the exit of the polymerization tank was 60°C. The unreacted vinyl acetate monomer was removed by introducing methanol vapor into the polymerized liquid taken out continuously, and the methanol solution (concentration 32 mass %) of ethylene-vinyl acetate copolymer was obtained.

Then, in the methanol solution (concentration: 32% by mass) of the ethylene-vinyl acetate copolymer obtained in the aforementioned polymerization step, the molar ratio of sodium hydroxide relative to the vinyl acetate unit in the aforementioned ethylene-vinyl acetate copolymer was adjusted. The methanol solution (concentration 4 mass %) of sodium hydroxide was added so that the ear ratio might become 0.012. Furthermore, with respect to 100 parts by mass of the aforementioned ethylene-vinyl acetate copolymer, 0.00018 parts by mass of a methanol solution of sorbic acid (concentration: 10 mass %) was added, and the resulting mixture was mixed with a static mixer, and then placed on a transporter. The tape was kept at 40°C for 18 minutes to allow the saponification reaction to proceed. Then, the aforementioned mixture was pulverized and dried to obtain an ethylene-vinyl alcohol copolymer (EVOH-24). As a result of the analysis, the content of ethylene units was 2 mol %, the viscosity average degree of polymerization was 1,700, the degree of saponification was 98.5 mol %, the content of structure (I) was 0.00114 mol %, and the content of structure (II) was 0.0002 mol %. Ear %, the block character of the ethylene unit is 0.95.

<Example 47> 83.0 kg of VAM-1 and 26.6 kg of methanol were supplied to a 250L pressurized reaction tank equipped with a jacket, a stirrer, a nitrogen introduction port, an ethylene introduction port, and a starter addition port, and the temperature was raised to 60°C, followed by nitrogen bubbling for 30 minutes, nitrogen substitution was performed in the reaction tank. Next, the pressure of the reaction tank (ethylene pressure) was increased to 3.6 MPa and ethylene was introduced. As the ethylene system, sugarcane-derived ethylene (manufactured by Braskem S.A.) was used. After adjusting the temperature in the reaction tank to 60°C, 2.5 g/L of 2,2'-azobis(2,4-dimethylvaleronitrile) was supplied in an initial supply amount of 362 mL and a continuous supply amount of 1,120 mL/hr. methanol solution as the starting agent. During the polymerization, the ethylene pressure was maintained at 3.6 MPa, and the polymerization temperature was maintained at 60°C. When the polymerization rate of vinyl acetate was about 40%, sorbic acid was added, and the polymerization was stopped by cooling. After the reaction tank was opened for deethylene, nitrogen was bubbled to complete deethylene. Next, after removing unreacted vinyl acetate under reduced pressure, methanol was added to the obtained ethylene-vinyl acetate copolymer as a 20 mass % methanol solution.

The methanol solution of the obtained ethylene-vinyl acetate copolymer was added to the saponification reactor, and a 2 mol/L methanol solution of sodium hydroxide was added to make 3 equivalents of the vinyl ester component in the copolymer. It prepared so that the copolymer concentration might be 5%. The temperature of this solution was raised to 60°C, and the saponification reaction was performed for 3 hours while stirring. At this time, the ultrasonic cleaner US CLEANER USK-2R was used for the last hour, and the reaction was performed while irradiating ultrasonic waves through the reactor at an output of 80 W and a frequency of 40 kHz. Then, acetic acid and water were added to stop the saponification reaction, and the ethylene-vinyl alcohol copolymer was precipitated. The precipitated ethylene-vinyl alcohol copolymer was recovered and chopped to obtain water-containing fragments, which were washed with an aqueous acetic acid solution and ion-exchanged water, and then immersed in an aqueous solution containing sodium acetate and acetic acid. This aqueous solution was separated from the water-containing chips and deliquored, and then placed in a hot-air dryer for drying at 80° C. for 3 hours and then at 110° C. for 35 hours to obtain ethylene-vinyl alcohol copolymer (EVOH-25) as dry chips. As a result of the analysis, the degree of saponification was 99.9 mol % or more, the content of structure (I) was 0.0071 mol %, and the content of structure (II) was 0.0027 mol %. In addition, the content of sodium and acetic acid was 180 ppm and 300 ppm, respectively.

<Example 48> Tracking was performed by the following method. The barrier layer containing the ethylene-vinyl alcohol copolymer was taken from a sample of a commercially available packaging container 10 . For this sample, ¹⁴ C/C and δ ¹³ C were obtained by the aforementioned method. The obtained value is compared with the values of ¹⁴ C/C and δ ¹³ C recorded in advance at the time of manufacture, thereby determining whether it is an in-house product.

<Example 49> Using the EVOH-1 to EVOH-6 obtained in the aforementioned Examples 8 to 13, the films 1 to 6 were obtained by the aforementioned method. The obtained films 1 to 6 were recovered as packaging bags 1 to 6, respectively. The values of ¹⁴ C/C and δ ¹³ C of the recovered product were measured by the aforementioned methods, and the results were consistent with the values obtained in Examples 8 to 13. [Possibility of Industrial Use]

The vinyl acetate of the present invention is different from the conventional vinyl acetate in that the value of ¹⁴ C/C is different. Therefore, the vinyl alcohol polymer including the vinyl acetate polymer obtained by polymerizing the vinyl acetate of the present invention as a monomer unit and its saponification product also has a value of ¹⁴ C/C different from that of the conventional product. Using this difference, it can be determined whether the vinyl acetate polymer or vinyl alcohol polymer recovered from the market is the one using the vinyl acetate of the present invention, and the tracking of the products of the own company can be carried out.

1: Polymerization tank 2: heat exchanger 3~7: Catheter 8: Blender 9: Reaction solution outlet tube 10: Vinyl ester introduction pipe 11,12: Refrigerant pipe 13: Gas discharge pipe 21:MAXBLEND Wing

FIG. 1 is a schematic diagram of the polymerization apparatus used in Example 46. FIG. FIG. 2 is a schematic view of a stirring blade used in Example 46. FIG.

none.

Claims (32)

A vinyl acetate in which the ratio of carbon 14 to all carbons is 1.0×10 ⁻¹⁴ or more. The vinyl acetate of claim 1, wherein the carbon stable isotope ratio is -20‰ or more. The vinyl acetate of claim 1, wherein the carbon stable isotope ratio is less than -20‰. The vinyl acetate according to any one of claims 1 to 3, which contains more than 0 ppm and 100 ppm or less of a sulfur component. The vinyl acetate of claim 4, wherein the sulfur component is dimethyl sulfide or dimethyl sulfoxide. The vinyl acetate of any one of claims 1 to 5, comprising 10 ppm to 1,500 ppm of acetate. The vinyl acetate of claim 6, wherein the acetate is at least one of methyl acetate and ethyl acetate. The vinyl acetate according to any one of claims 1 to 7, which contains more than 0 ppm and less than 100 ppm of a polymerization inhibitor. The vinyl acetate according to any one of claims 1 to 8, comprising 1 ppm to 500 ppm of at least one compound selected from polycarboxylic acids, hydroxycarboxylic acids, and hydroxylactone-based compounds. The vinyl acetate according to any one of claims 1 to 9, comprising 0.001 to 10 parts by mass of acetaldehyde dimethyl acetal. A vinyl acetate polymer containing vinyl acetate as claimed in any one of claims 1 to 10 as a monomer unit. A vinyl alcohol polymer obtained by saponifying the vinyl acetate polymer of claim 11. The vinyl alcohol polymer of claim 12, further comprising ethylene units, the content of which is 1 mol% or more and 60 mol% or less. As claimed in the vinyl alcohol polymer of claim 12 or 13, its saponification degree is above 80 mol%. The vinyl alcohol polymer according to any one of claims 12 to 14, wherein the viscosity average degree of polymerization is 200 or more and 5,000 or less. The vinyl alcohol polymer according to any one of claims 12 to 15, wherein the content of the 1,2-diol bond is 0.2 mol % or more and 2 mol % or less. The vinyl alcohol polymer of any one of claims 12 to 16, wherein the ratio of carbon 14 to all carbons is 1.0×10 ⁻¹⁴ or more. The vinyl alcohol polymer of any one of claims 12 to 17, wherein the carbon stable isotope ratio is -20‰ or more. The vinyl alcohol polymer of any one of claims 12 to 17, wherein the carbon stable isotope ratio is less than -20‰. The vinyl alcohol polymer according to any one of claims 12 to 19, which contains a sulfur content of more than 0 ppm and less than 100 ppm. The vinyl alcohol polymer of claim 20, wherein the sulfur component is dimethyl sulfide or dimethyl sulfoxide. The vinyl alcohol polymer of any one of claims 12 to 21, wherein the ethylene unit content is 1 mol % or more and 15 mol % or less, and the degree of saponification is 85 mol % or more and 99.9 mol % or less, The polymer terminal has a propyl group, and the content of the propyl group is 0.0005 mol % or more and 0.1 mol % or less with respect to all the monomer units. The vinyl alcohol polymer according to any one of claims 12 to 22, wherein the polymer terminal has an alkoxy group, and the content of the alkoxy group is 0.0005 mol % or more and 1 mol % or less with respect to all monomer units. The vinyl alcohol polymer according to any one of claims 12 to 23, wherein the polymer terminal has the following structures (I) and (II), and the total content of the structures (I) and (II) is relative to the constituent vinyl alcohol All monomer units of the polymer are 0.001 mol% or more and 0.1 mol% or less,

(in the formula, Y is a hydrogen atom or a methyl group)

(in the formula, Z is a hydrogen atom or a methyl group). The vinyl alcohol polymer of claim 24, wherein the ethylene unit content is 1 mol% or more and 15 mol% or less, and the degree of saponification is 85 mol% or more and 99.9 mol% or less, The molar ratio R[I/(I+II)] of the structure (I) to the total amount of the structure (I) and the structure (II) satisfies the following formula (1): R＜0.92-Et/100 (1) (In the formula (1), Et is the ethylene unit content (mol %)). The vinyl alcohol polymer of any one of claims 13, 22 or 25, wherein the ethylene units have a block character of 0.90 to 0.99. The vinyl alcohol polymer of claim 24 or 25, wherein the ethylene unit content is 15 mol% or more and 60 mol% or less, and the degree of saponification is 85 mol% or more and 99.9 mol% or less, The total content of the structure (I) and the structure (II) is 0.002 mol % or more and 0.02 mol % or less with respect to all monomer units constituting the vinyl alcohol polymer, and the structure (I) is relative to the structure (I). ) and the total molar ratio R[I/(I+II)] of the structure (II) satisfies the following formula (2) expressed using the ethylene unit content Et in the vinyl alcohol polymer: 0.8<R+Et/100 (2). A tracking method for polymers using vinyl acetate having a ratio of carbon 14 to all carbons of 1.0×10 ⁻¹⁴ or more. A method for tracing a polymer, which uses vinyl acetate as claimed in claim 28, the vinyl acetate having a carbon stable isotope ratio of -20‰ or more. A method of tracing polymers using vinyl acetate as claimed in claim 28, the vinyl acetate having a carbon stable isotope ratio of less than -20‰. A method of tracing a polymer using a vinyl acetate polymer containing vinyl acetate as in any one of claims 28 to 30 as a monomer unit. A method for tracing polymers using vinyl alcohol polymers obtained by saponifying the vinyl acetate polymer of claim 31.

Images